Hello,
as a normal user I cannot start xfce4. I can as root, but not as normal user. I ssh'd to the machine and started xfce4 so that I could copy out the whole error. Please let me know on how to fix the permission errors, since I think it could happen to anyone. Also my user is in the video group...:

[mini@Minifsk ~]$ startxfce4
/usr/bin/startxfce4: Starting X server


This is a pre-release version of the X server from The X.Org Foundation.
It is not supported in any way.
Bugs may be filed in the bugzilla at http://bugs.freedesktop.org/.
Select the "xorg" product for bugs you find in this release.
Before reporting bugs in pre-release versions please check the
latest version in the X.Org Foundation git repository.
See http://wiki.x.org/wiki/GitPage for git access instructions.

X.Org X Server 1.4.0.90
Release Date: 5 September 2007
X Protocol Version 11, Revision 0
Build Operating System: Linux 2.6.24-ARCH i686
Current Operating System: Linux Minifsk 2.6.22-ARCH #1 SMP PREEMPT Wed Sep 26 20:57:40 CEST 2007 i586
Build Date: 20 February 2008 07:56:55PM

Before reporting problems, check http://wiki.x.org
to make sure that you have the latest version.
Module Loader present
Markers: (--) probed, (**) from config file, (==) default setting,
(++) from command line, (!!) notice, (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Mon Feb 25 15:53:17 2008
(==) Using config file: "/etc/X11/xorg.conf"
(II) Module "ddc" already built-in
(EE) Failed to load module "type1" (module does not exist, 0)
Unable to open /dev/cpu/0/msr: 2
(II) Module "ddc" already built-in
(II) Module "ramdac" already built-in
expected keysym, got XF86KbdLightOnOff: line 70 of pc
expected keysym, got XF86KbdBrightnessDown: line 71 of pc
expected keysym, got XF86KbdBrightnessUp: line 72 of pc
expected keysym, got XF86KbdLightOnOff: line 70 of pc
expected keysym, got XF86KbdBrightnessDown: line 71 of pc
expected keysym, got XF86KbdBrightnessUp: line 72 of pc
Could not init font path element /usr/share/fonts/TTF, removing from list!
mkdtemp: private socket dir: Permission denied

(xfce4-session:4634): GLib-WARNING **: GError set over the top of a previous GError or uninitialized memory.
This indicates a bug in someone's code. You must ensure an error is NULL before it's set.
The overwriting error message was: Failed to create file '/tmp/.xfsm-ICE-1TX96T': Permission denied

** (xfce4-session:4634): WARNING **: Unable to open temporary file: @\x95\u0003
*** glibc detected *** /usr/bin/xfce4-session: free(): invalid pointer: 0xb7991678 ***
======= Backtrace: =========
/lib/libc.so.6[0xb778e836]
/lib/libc.so.6(cfree+0x89)[0xb77904d9]
/usr/lib/libglib-2.0.so.0(g_free+0x31)[0xb78e5af1]
/usr/lib/libglib-2.0.so.0(g_error_free+0x29)[0xb78cf719]
/usr/bin/xfce4-session[0x804f199]
/usr/bin/xfce4-session[0x804f2f3]
/usr/bin/xfce4-session[0x805144c]
/usr/bin/xfce4-session[0x804f98f]
/lib/libc.so.6(__libc_start_main+0xe0)[0xb773d390]
/usr/bin/xfce4-session[0x804f001]
======= Memory map: ========
08048000-0805d000 r-xp 00000000 08:01 9057369 /usr/bin/xfce4-session
0805d000-0805e000 rw-p 00015000 08:01 9057369 /usr/bin/xfce4-session
0805e000-080a0000 rw-p 0805e000 00:00 0 [heap]
b7200000-b7221000 rw-p b7200000 00:00 0
b7221000-b7300000 ---p b7221000 00:00 0
b7305000-b7365000 rw-s 00000000 00:08 1114123 /SYSV00000000 (deleted)
b7379000-b7383000 r-xp 00000000 08:01 2150441 /usr/lib/libgcc_s.so.1
b7383000-b7384000 rw-p 00009000 08:01 2150441 /usr/lib/libgcc_s.so.1
b738e000-b7397000 r-xp 00000000 08:01 14680921 /lib/libnss_files-2.7.so
b7397000-b7399000 rw-p 00008000 08:01 14680921 /lib/libnss_files-2.7.so
b7399000-b754a000 r--p 00000000 08:01 10633827 /usr/lib/locale/locale-archive
b754a000-b754c000 rw-p b754a000 00:00 0
b754c000-b756a000 r-xp 00000000 08:01 2387165 /usr/lib/libexpat.so.1.5.2
b756a000-b756c000 rw-p 0001e000 08:01 2387165 /usr/lib/libexpat.so.1.5.2
b756c000-b7570000 r-xp 00000000 08:01 2392516 /usr/lib/libXdmcp.so.6.0.0
b7570000-b7571000 rw-p 00003000 08:01 2392516 /usr/lib/libXdmcp.so.6.0.0
b7571000-b7573000 r-xp 00000000 08:01 2392513 /usr/lib/libXau.so.6.0.0
b7573000-b7574000 rw-p 00001000 08:01 2392513 /usr/lib/libXau.so.6.0.0
b7574000-b7575000 rw-p b7574000 00:00 0
b7575000-b759b000 r-xp 00000000 08:01 14745263 /lib/libpcre.so.0.0.1
b759b000-b759c000 rw-p 00025000 08:01 14745263 /lib/libpcre.so.0.0.1
b759c000-b75ad000 r-xp 00000000 08:01 14736294 /lib/libz.so.1.2.3
b75ad000-b75ae000 rw-p 00010000 08:01 14736294 /lib/libz.so.1.2.3
b75ae000-b7625000 r-xp 00000000 08:01 2445301 /usr/lib/libfreetype.so.6.3.16
b7625000-b7629000 rw-p 00077000 08:01 2445301 /usr/lib/libfreetype.so.6.3.16
b7629000-b7655000 r-xp 00000000 08:01 2547792 /usr/lib/libpangoft2-1.0.so.0.1800.4
b7655000-b7656000 rw-p 0002c000 08:01 2547792 /usr/lib/libpangoft2-1.0.so.0.1800.4
b7656000-b765e000 r-xp 00000000 08:01 2516896 /usr/lib/libXcursor.so.1.0.2
b765e000-b765f000 rw-p 00007000 08:01 2516896 /usr/lib/libXcursor.so.1.0.2
b765f000-b7660000 rw-p b765f000 00:00 0
b7660000-b7665000 r-xp 00000000 08:01 2472309 /usr/lib/libXrandr.so.2.1.0
b7665000-b7666000 rw-p 00005000 08:01 2472309 /usr/lib/libXrandr.so.2.1.0
b7666000-b766d000 r-xp 00000000 08:01 2472258 /usr/lib/libXi.so.6.0.0
b766d000-b766e000 rw-p 00006000 08:01 2472258 /usr/lib/libXi.so.6.0.0
b766e000-b7670000 r-xp 00000000 08:01 2503340 /usr/lib/libXinerama.so.1.0.0
b7670000-b7671000 rw-p 00001000 08:01 2503340 /usr/lib/libXinerama.so.1.0.0
b7671000-b7678000 r-xp 00000000 08:01 2472265 /usr/lib/libXrender.so.1.3.0
b7678000-b7679000 rw-p 00007000 08:01 2472265 /usr/lib/libXrender.so.1.3.0
b7679000-b7686000 r-xp 00000000 08:01 2392474 /usr/lib/libXext.so.6.4.0
b7686000-b7687000 rw-p 0000c000 08:01 2392474 /usr/lib/libXext.so.6.4.0
b7687000-b76af000 r-xp 00000000 08:01 2387198 /usr/lib/libfontconfig.so.1.3.0
b76af000-b76b0000 rw-p 00028000 08:01 2387198 /usr/lib/libfontconfig.so.1.3.0
b76b0000-b76b1000 rw-p b76b0000 00:00 0
b76b1000-b76d4000 r-xp 00000000 08:01 14680919 /lib/libm-2.7.so
b76d4000-b76d6000 rw-p 00022000 08:01 14680919 /lib/libm-2.7.so
b76d6000-b76f8000 r-xp 00000000 08:01 2516903 /usr/lib/libpng12.so.0.24.0
b76f8000-b76f9000 rw-p 00021000 08:01 2516903 /usr/lib/libpng12.so.0.24.0
b76f9000-b76fd000 r-xp 00000000 08:01 2503368 /usr/lib/libXfixes.so.3.1.0
b76fd000-b76fe000 rw-p 00003000 08:01 2503368 /usr/lib/libXfixes.so.3.1.0
b76fe000-b7700000 r-xp 00000000 08:01 2516879 /usr/lib/libXdamage.so.1.1.0
b7700000-b7701000 rw-p 00001000 08:01 2516879 /usr/lib/libXdamage.so.1.1.0
b7701000-b7703000 r-xp 00000000 08:01 2571381 /usr/lib/libXcomposite.so.1.0.0
b7703000-b7704000 rw-p 00001000 08:01 2571381 /usr/lib/libXcomposite.so.1.0.0
b7704000-b7705000 rw-p b7704000 00:00 0
b7705000-b770c000 r-xp 00000000 08:01 2657428 /usr/lib/libstartup-notification-1.so.0.0.0
b770c000-b770d000 rw-p 00006000 08:01 2657428 /usr/lib/libstartup-notification-1.so.0.0.0
b770d000-b7724000 r-xp 00000000 08:01 2392610 /usr/lib/libxcb.so.1.0.0
b7724000-b7725000 rw-p 00016000 08:01 2392610 /usr/lib/libxcb.so.1.0.0
b7725000-b7726000 r-xp 00000000 08:01 2392560 /usr/lib/libxcb-xlib.so.0.0.0
b7726000-b7727000 rw-p 00000000 08:01 2392560 /usr/lib/libxcb-xlib.so.0.0.0
b7727000-b7857000 r-xp 00000000 08:01 14680935 /lib/libc-2.7.so
b7857000-b7858000 r--p 00130000 08:01 14680935 /lib/libc-2.7.so
b7858000-b785a000 rw-p 00131000 08:01 14680935 /lib/libc-2.7.so
b785a000-b785d000 rw-p b785a000 00:00 0
b785d000-b78ae000 r-xp 00000000 08:01 2330646 /usr/lib/libdbus-1.so.3.2.0
b78ae000-b78af000 rw-p 00051000 08:01 2330646 /usr/lib/libdbus-1.so.3.2.0
b78af000-b794e000 r-xp 00000000 08:01 2547666 /usr/lib/libglib-2.0.so.0.1400.5
b794e000-b794f000 rw-p 0009f000 08:01 2547666 /usr/lib/libglib-2.0.so.0.1400.5
b794f000-b7950000 rw-p b794f000 00:00 0
b7950000-b7952000 r-xp 00000000 08:01 14680928 /lib/libdl-2.7.so
b7952000-b7954000 rw-p 00001000 08:01 14680928 /lib/libdl-2.7.so
b7954000-b7957000 r-xp 00000000 08:01 2547665 /usr/lib/libgmodule-2.0.so.0.1400.5
b7957000-b7958000 rw-p 00002000 08:01 2547665 /usr/lib/libgmodule-2.0.so.0.1400.5
b7958000-b7991000 r-xp 00000000 08:01 2547658 /usr/lib/libgobject-2.0.so.0.1400.5
b7991000-b7992000 rw-p 00039000 08:01 2547658 /usr/lib/libgobject-2.0.so.0.1400.5
b7992000-b7a06000 r-xp 00000000 08:01 2547710 /usr/lib/libcairo.so.2.11.7
b7a06000-b7a08000 rw-p 00073000 08:01 2547710 /usr/lib/libcairo.so.2.11.7
b7a08000-b7a42000 r-xp 00000000 08:01 2547790 /usr/lib/libpango-1.0.so.0.1800.4
b7a42000-b7a44000 rw-p 00039000 08:01 2547790 /usr/lib/libpango-1.0.so.0.1800.4
b7a44000-b7a4c000 r-xp 00000000 08:01 2547787 /usr/lib/libpangocairo-1.0.so.0.1800.4
b7a4c000-b7a4d000 rw-p 00007000 08:01 2547787 /usr/lib/libpangocairo-1.0.so.0.1800.4
b7a4d000-b7a4e000 rw-p b7a4d000 00:00 0
b7a4e000-b7a67000 r-xp 00000000 08:01 2586914 /usr/lib/libgdk_pixbuf-2.0.so.0.1200.7
b7a67000-b7a68000 rw-p 00018000 08:01 2586914 /usr/lib/libgdk_pixbuf-2.0.so.0.1200.7
b7a68000-b7a80000 r-xp 00000000 08:01 2547698 /usr/lib/libatk-1.0.so.0.2009.1
b7a80000-b7a82000 rw-p 00017000 08:01 2547698 /usr/lib/libatk-1.0.so.0.2009.1
b7a82000-b7b02000 r-xp 00000000 08:01 2571418 /usr/lib/libgdk-x11-2.0.so.0.1200.7
b7b02000-b7b05000 rw-p 00080000 08:01 2571418 /usr/lib/libgdk-x11-2.0.so.0.1200.7
b7b05000-b7b11000 r-xp 00000000 08:01 2330633 /usr/lib/libxfce4util.so.4.0.2
b7b11000-b7b12000 rw-p 0000b000 08:01 2330633 /usr/lib/libxfce4util.so.4.0.2
b7b12000-b7b13000 rw-p b7b12000 00:00 0
b7b13000-b7e76000 r-xp 00000000 08:01 2586913 /usr/lib/libgtk-x11-2.0.so.0.1200.7
b7e76000-b7e7c000 rw-p 00363000 08:01 2586913 /usr/lib/libgtk-x11-2.0.so.0.1200.7
b7e7c000-b7e7e000 rw-p b7e7c000 00:00 0
b7e7e000-b7ec5000 r-xp 00000000 08:01 2657437 /usr/lib/libxfcegui4.so.4.2.6
b7ec5000-b7ec7000 rw-p 00047000 08:01 2657437 /usr/lib/libxfcegui4.so.4.2.6
b7ec7000-b7ecb000 r-xp 00000000 08:01 2657435 /usr/lib/libxfce4mcs-client.so.3.0.5
b7ecb000-b7ecc000 rw-p 00003000 08:01 2657435 /usr/lib/libxfce4mcs-client.so.3.0.5
b7ecc000-b7fb1000 r-xp 00000000 08:01 2392455 /usr/lib/libX11.so.6.2.0
b7fb1000-b7fb5000 rw-p 000e4000 08:01 2392455 /usr/lib/libX11.so.6.2.0
b7fb5000-b7fc9000 r-xp 00000000 08:01 2392478 /usr/lib/libICE.so.6.3.0
b7fc9000-b7fca000 rw-p 00014000 08:01 2392478 /usr/lib/libICE.so.6.3.0
b7fca000-b7fcc000 rw-p b7fca000 00:00 0
b7fcc000-b7fd3000 r-xp 00000000 08:01 2392489 /usr/lib/libSM.so.6.0.0
b7fd3000-b7fd4000 rw-p 00006000 08:01 2392489 /usr/lib/libSM.so.6.0.0
b7fd4000-b7fd7000 r-xp 00000000 08:01 2692611 /usr/lib/libxfsm-4.2.so.0.0.1
b7fd7000-b7fd8000 rw-p 00002000 08:01 2692611 /usr/lib/libxfsm-4.2.so.0.0.1
b7fd8000-b7fd9000 rw-p b7fd8000 00:00 0
b7fd9000-b7fe2000 r-xp 00000000 08:01 6325291 /usr/lib/xfce4/splash/engines/libmice.so
b7fe2000-b7fe3000 rw-p 00009000 08:01 6325291 /usr/lib/xfce4/splash/engines/libmice.so
b7fe3000-b7fe4000 r-xp b7fe3000 00:00 0 [vdso]
b7fe4000-b7ffe000 r-xp 00000000 08:01 14680901 /lib/ld-2.7.so
b7ffe000-b8000000 rw-p 0001a000 08:01 14680901 /lib/ld-2.7.so
bffb7000-bffcc000 rw-p bffb7000 00:00 0 [stack]
/etc/xdg/xfce4/xinitrc: line 84: 4634 Aborted $xfcesm
SSH_AGENT_PID not set, cannot kill agent

waiting for X server to shut down FreeFontPath: FPE "/usr/share/fonts/misc:unscaled" refcount is 2, should be 1; fixing.