Arch Linux

Description:
After installing zim, I got the error "WARNING: Can not import 'xdg.Mime' - falling back to 'mimetypes'"
I then installed pyxdg. They error message went away, but zim would still not launch. I then ran 'zim --gui -D' and it looks like xdg-open was not working correctly(output down below). After installing firefox, zim starts up fine

I feel that firefox should be added to the dependencies for this package. Perhaps 'pyxdg' should be added as an optional dep.

Additional info:
Version: 0.48-1

-- After installing pyxdg --
$ zim --gui -D
INFO: This is zim 0.48
DEBUG: Python version is (2, 6, 5, 'final', 0)
DEBUG: Platform is posix
DEBUG: Zim revision is:
branch: pyzim-trunk
revision: 290 pardus@cpan.org-20100722213310-1qj38a5ozyxy06ya
date: 2010-07-22 23:33:10 +0200

DEBUG: Not running from a source dir
DEBUG: Set XDG_DATA_HOME to /home/ching/.local/share
DEBUG: Set XDG_DATA_DIRS to [<Dir: /usr/share>, <Dir: /usr/local/share>]
DEBUG: Set XDG_CONFIG_HOME to /home/ching/.config
DEBUG: Set XDG_CONFIG_DIRS to [<Dir: /etc/xdg>]
DEBUG: Set XDG_CACHE_HOME to /home/ching/.cache
DEBUG: Running command: gui
DEBUG: Cache dir: /home/ching/school/zim/.zim
DEBUG: Loading /home/ching/school/zim/notebook.zim
DEBUG: Index database file: /home/ching/school/zim/.zim/index.db
INFO: Opening default notebook
INFO: Starting UnixSocketDaemon
DEBUG: Socket address: /tmp/zim-ching/daemon-socket
DEBUG: Wrote /tmp/zim-ching/daemon.pid
DEBUG: Sending to daemon: ["ping",[],{}]

DEBUG: Daemon replied: "Ack"
DEBUG: Sending to daemon: ["vivicate",["zim.gui.GtkInterface","file:///home/ching/school/zim"],{"usedaemon":true,"notebook":"file:///home/ching/school/zim"}]

DEBUG: Child spawned 24409 (u'zim.gui.GtkInterface', u'file:///home/ching/school/zim')
DEBUG: No such signal: notebook-list-changed
DEBUG: Daemon replied: true
DEBUG: Sending to daemon: ["relay",[["zim.gui.GtkInterface","file:///home/ching/school/zim"],"present",null],{"geometry":null,"fullscreen":null}]

DEBUG: Sending to child 24409: ["present",[null],{"geometry":null,"fullscreen":null}]

DEBUG: Daemon replied: true
** Message: pygobject_register_sinkfunc is deprecated (GtkWindow)
** Message: pygobject_register_sinkfunc is deprecated (GtkInvisible)
** Message: pygobject_register_sinkfunc is deprecated (GtkObject)
DEBUG: Loading /home/ching/.config/zim/preferences.conf
DEBUG: Gtk version is (2, 20, 1)
DEBUG: Pygtk version is (2, 17, 0)
WARNING: Could not find all icon sizes for the application icon
DEBUG: Loading /usr/share/zim/applications/firefox.desktop
DEBUG: Loading /usr/share/zim/applications/thunderbird.desktop
DEBUG: Loading /usr/share/zim/applications/xdg-email.desktop
DEBUG: Loading /usr/share/zim/applications/xdg-open.desktop
DEBUG: Loading /usr/share/applications/chromium.desktop
ERROR: Error in child main:
Traceback (most recent call last):
File "/usr/lib/python2.6/site-packages/zim/daemon.py", line 541, in spawn
self._main()
File "/usr/lib/python2.6/site-packages/zim/daemon.py", line 564, in _main
obj = klassobj(*args, **kwargs)
File "/usr/lib/python2.6/site-packages/zim/gui/__init__.py", line 345, in __init__
helpers = get_helper_applications(type)
File "/usr/lib/python2.6/site-packages/zim/gui/applications.py", line 149, in get_helper_applications
for entry in get_applications('text/html'):
File "/usr/lib/python2.6/site-packages/zim/gui/applications.py", line 92, in get_applications
entries.append(WebBrowser())
File "/usr/lib/python2.6/site-packages/zim/applications.py", line 151, in __init__
self.controller = webbrowser.get()
File "/usr/lib/python2.6/webbrowser.py", line 52, in get
raise Error("could not locate runnable browser")
Error: could not locate runnable browser
DEBUG: Child exited 24409 (u'zim.gui.GtkInterface', u'file:///home/ching/school/zim')
INFO: Last instance quit - exiting daemon
INFO: Stopped UnixSocketDaemon

Steps to reproduce:
Install zim without firefox installed