Hi,
My default browser is IE 7, but I personally use Firefox. I can get onto the forum with either one, no problem.
Since my wife is familiar with IE7 and prefers no changes ever in her life, I let her merilly go on with IE, while I use FF.
Makes me happy and keeps her not mad at me for changing something.
This didn't really answer your questions, but my suggestion would be to check security. I know the site is tweaked for Firefox.
Regards
Harry Thomas
LE 104EZ, CNO