From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.8) Gecko/20050512 Red Hat/1.0.4-1.4.1 Firefox/1.0.4

Description of problem:
Firefox justs wants to download the theme and open with the archive manager,
or save it to the disk.

Version-Release number of selected component (if applicable):
firefox-1.0.4-1.4.1

How reproducible:
Always

Steps to Reproduce:
1.  Open firefox and select tools:themes
2.  Click on "Get More Themes"
3.  Click on a theme install icon.
  

Actual Results:  Firefox wants to download it as a regular file.

Expected Results:  I thought Firefox used to actually install the theme?

Additional info:

I have this problem on RHEL4 and FC3.

Under FC3 I have some themes already installed, so I am presuming this feature used to work but has become broken due to a program update through up2date.