You've upgraded to iManager 2.5 or higher, and now Firefox will no longer render the pages correctly.
There is apparently a bug in Firefox that can cause this.
To remedy the problem,
1. In the URL string, type "about:config"
2. Find the line that says "signed.applets.codebase_principal_support" and make sure the value is set to: FALSE.
3. Exit Firefox and edit the prefs.js file.
4. Remove all lines from the file that show the following:
Disclaimer: As with everything else at Cool Solutions, this content is definitely not supported by Novell (so don't even think of calling Support if you try something and it blows up).
It was contributed by a community member and is published "as is." It seems to have worked for at least one person, and might work for you. But please be sure to test, test, test before you do anything drastic with it.