As Luxor said, its not dependant on Active-X.. However when I gave it a second thought you need to allow cookies or you will fail to stay logged in..
Please check Tools > Options > Privacy.. Make sure you have those boxes where it says "cookies" checked..
Yes, I allow cookies. However, I depend on a cookie management extension called Permit Cookies (
http://mfe.gorgias.de/).
I just tried deleting all Comodo cookies and then came back to the forum but still the same problem.
I tired changing the remain logged in time from forever to 1 hour but that made no difference.
I then tried to logon through IE 8. No problems at all!
So I'd say that the Comodo forum software appears to have some problems with FF or some combination of FF plug-in's and/or extensions.