Sandbox seems to disable Java script

Hi
I have been sandboxing my browsers (Iexplore, Firefox and Chrome) for a few months.
Now I can’t log in to my netbank. There is a Java script creating the log in dialog box.
In Iexplore I get an error message. The two other browsers just don’t show the log in dialog.
Without sandbox there is no problem.
Internet explorer 9 64 bit.
64 bit machine. Windows 7.
Avast Internet Security 7.

Please advise
FlemmingK