For the sake of completeness, I should say that I'm running on FC5 with my updated gstreamer stack installed into a separate prefix. I then just copied the plugin .so's into the standard /usr/lib/mozilla/plugins. So the crash might be due to two versions of GTK being loaded in the same process and stuff. On the other hand, the error message is still and issue, and I have gotten other embedded videos to play successfully.

Firefox crashes?
Please get the output of "firefox -debug" when this problem happens, I bet it's a missing symbol. Otherwise, this is a dupe of bug 350912

Here's the complete output. In short, you're right:

/usr/lib/mozilla/plugins/libtotem-gmp-plugin.so: undefined symbol: _ZN8nsMemory5AllocEj

===========================

** Message: NP_Initialize

** Message: totem_plugin_new_instance
totemGMPPlugin ctor [0xa459f60]
mode 1
mime type: application/x-mplayer2
argv[0] name Player
argv[1] src http://moses.gametrailers.com/streambuilder.php?type=wmv&streamtext=ad:black_short::m:t_whiteknightstory_tgs06_h264::m:black
argv[2] type application/x-mplayer2
argv[3] showc
argv[4] showstatusbar 1
argv[5] autosize true
argv[6] loop true
argv[7] enablec
argv[8] 0
argv[9] displaysize 0
argv[10] pluginspage http://www.microsoft.com/Windows/Downloads/Contents/Products/MediaPlayer/
argv[11] height 552
argv[12] width 852
** Message: plugin_get_value 14 (e)

** Message: plugin_set_window
** Message: waiting for data to come
** Message: leaving plugin_set_window
** Message: plugin_set_window
** Message: existing window
** Message: resize
** Message: leaving plugin_set_window
** Message: plugin_set_window
** Message: existing window
** Message: resize
** Message: leaving plugin_set_window
** Message: plugin_new_stream
** Message: plugin_new_stream type: video/x-ms-asf url: http://moses.gametrailers.com/streambuilder.php?type=wmv&streamtext=ad:black_short::m:t_whiteknightstory_tgs06_h264::m:black
** Message: Is special type 'audio/x-ms-asx'

** Message: Need to wait for the file to be downloaded completely
** Message: plugin_stream_as_file: /tmp/plugtmp-5/streambuilder.php
** Message: Launching: /opt/bleedingedge/libexec/totem-mozilla-viewer --xid 60821441 --width 852 --height 552 --url http://moses.gametrailers.com/streambuilder.php?type=wmv&streamtext=ad:black_short::m:t_whiteknightstory_tgs06_h264::m:black --mimetype video/x-msvideo --repeat --playlist file:///tmp/plugtmp-5/streambuilder.php

** Message: waiting for signal org.totem_5107.MozillaPluginService
** Message: Received notification for :1.35

** Message: Received notification for :1.35

** Message: Received notification for org.totem_5107.MozillaPluginService

** Message: Received notification for org.totem_5107.MozillaPluginService

** Message: Done forking, new proxy=0xa1ab2c0
** Message: plugin_destroy_stream, reason: 0
** Message: plugin_get_value 15 (f)

** Message: unhandled variable 15 (f)
** Message: plugin_get_value 11 (b)

** Message: plugin_get_value 268435466 (1000000a)

** Message: GetHelperForLanguage 2
/usr/lib/firefox-1.5.0.7/firefox-bin: symbol lookup error: /usr/lib/mozilla/plugins/libtotem-gmp-plugin.so: undefined symbol: _ZN8nsMemory5AllocEj

The program 'totem-mozilla-viewer' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadWindow (invalid Window parameter)'.
  (Details: serial 108 error_code 3 request_code 18 minor_code 0)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)

===========================

Thanks for the bug report. This particular bug has already been reported into our bug tracking system, but please feel free to report any further bugs you find.


*** This bug has been marked as a duplicate of 354490 ***