Comment 34 for bug 153055

Same here on hardy with english as main language
more over both firefox & thunderbird crash right after starting without any actions

ubuntu
      Linux xxx 2.6.24-23-generic #1 SMP Thu Nov 27 18:44:42 UTC 2008 i686 GNU/Linux
thunderbird
      version 2.0.0.19 (20090105),
firefox
      Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.5) Gecko/2008121621 Ubuntu/8.04 (hardy) Firefox/3.0.5
scim
      Smart Common Input Method 1.4.7

after closing scim tray applet
output of is "im-switch -l" below

Your input method setup under en_US locale as below.
=======================================================
The configuration "/home/xxx/.xinput.d/en_US" is defined as a link pointing to
scim
This private configuration supersedes the system wide default.
=======================================================
The system wide default is pointed by "/etc/alternatives/xinput-all_ALL" .
xinput-all_ALL - status is auto.
 link currently points to default
default - priority 10
default-xim - priority 0
none - priority 0
Current `best' version is default.
=======================================================
The available input method configuration files are:
default default-xim none scim scim-bridge scim-immodule th-xim
=======================================================