It is a known issue that OBIEE 11g does not support the Firefox browser version 10 or above (10/11/12).
My browser’s version:
Michal Novy’s workaround:
Open a new Firefox window or new tab. In the address bar type “about:config” and click enter. The following window appears. Click the “I’ll be careful, I promise!” button.
Click Right mouse button anywhere in the window and choose New –> String
Enter the preference name as “general.useragent.override” (without double colon)
Put the value “Mozilla/5.0 (Windows; Windows NT 6.1; rv:10.0) Gecko/20100101 Firefox/9.0” (without double colon)
Refresh OBIEE login screen and it should work now.
patch # 13564003 (Linux)
patch # 12877995 (Windows)
Till Next Time