Arch Linux

Description:
Instead of the browser part of miro (a major part of its GUI), there's only white space.

Additional info:
xulrunner 1.9
miro 1.2.3-2
miro 1.2.4-1 (compiled from source)

Some stuff miro dumps into the console - it's pretty much the same in v. 1.2.3:
INFO Starting up Miro
INFO OS: Linux
INFO Version: 1.2.4
INFO Revision: https://svn.participatoryculture.org/svn/dtv/tags/Miro-1.2.4/tv/resources - 7072
INFO Builder: peterix@peterix
INFO Build Time: 1215603427.51
INFO Starting event loop thread
INFO Restoring database...
INFO Connecting to /home/peterix/.miro/sqlitedb
TIMING Database load slow: 1.747
TIMING idle (finish startup) too slow (2.360 secs)
INFO Spawning auto downloader...
INFO *** Launching Downloader Daemon ****
WARNING Assuming port 80 for scheme: s
WARNING Assuming port 80 for scheme: s
WARNING Assuming port 80 for scheme: s
WARNING Assuming port 80 for scheme: s
WARNING Assuming port 80 for scheme: s
WARNING Assuming port 80 for scheme: s
WARNING Assuming port 80 for scheme: s
WARNING Assuming port 80 for scheme: s
WARNING Assuming port 80 for scheme: s
WARNING Assuming port 80 for scheme: s
TIMING Icon clear: 0.066
INFO Starting movie data updates
TIMING idle (finalizing startup) too slow (0.583 secs)
INFO Displaying main frame...
INFO Creating video display...
WARNING Menu item action "RenameVideo" not implemented
WARNING Menu item action "FastForward" not implemented
WARNING Menu item action "Rewind" not implemented
WARNING Menu item action "UpVolume" not implemented
WARNING Menu item action "DownVolume" not implemented
INFO Finished startup sequence
INFO loaded renderer 'xinerenderer'
TIMING gtkAsyncMethod: <function initRenderers at 0xb705302c> took too long: 2.009
WARNING! setupDummyBrowser failed
WARNING Error setting up drag and drop dummy element
WARNING! setupDragAndDrop failed
TIMING gtkSyncMethod: <function getDisplay at 0xb7069e2c> took too long: 2.073
INFO First URL is https://www.miroguide.com/
TIMING idle (select initial tab) too slow (2.087 secs)
WARNING! setupDragAndDrop failed
INFO *** Daemon ready ***
INFO Checking for updates...
TIMING timeout (Save database) too slow (0.956 secs)
TIMING timeout (Save database) too slow (0.521 secs)

Steps to reproduce:
Just start miro.