This is a script error that is shown in the Exchang10 email website itself? If so, it is likely an issue with how the email website is configured, and in other words not a problem with Firefox.

Maybe the email website wasn't tested in Firefox -- if this is for your work computer, try reaching out to your IT administrator who is responsible for the e-mail server and ask if they have an idea of what's going on here.

I have another tech who is using Firefox 10 and Windows XP and he logged into my email account and not having any issues like I reported with my Windows7 machine and Firefox 11.

I do not think it is anything with our Exchange email since I am not having this issue when running IE Version 9....

I found out that if I restart Firefox with add-ons disabled (in other words, run Firefox in SAFE MODE), my email problem disappeared...what would this indicate - should I disable all add-ons? or figure out which ones are causing a problem?

I also tried our Exchange10 email application from home with Firefox Version 9 and everything is fine....leads me to believe it still has something to do with the Add-Ons in Version 11....