Hi,
After having placed some support calls with Computer Associates, they have classified IE7 as unsupported for both the Brightstore & eTrust antivirus products.
If you have either of these products don't upgrade to IE7 as it WILL break the applications and Exchange 2003 if it is running.
They are working on upgrades for both of these products to address the problem, but they won't be available till some time in January.
Regards N Mc Donald