Exchange and IHateSpam error with Internet Explorer version

Personally I perfer a hardware device for spam blocking , but as a consultant you have to move and shake with what the customer has or is willing to purchase. The issue was when we had to re-install IHateSpam and it gave an error that we needed version 5.5 or higher for Internet Explorer to install and it would not. The server was on version 6.1 of IE. After trying all the basics, updates, etc.  We found a key in the registry that was causing the problem.

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Ole]
"DefaultLaunchPermission"

Problem description: You received Windows Installer Error 2731 or an Error 1720. There is a problem with this Windows Installer package.

In both cases, there were references to "A script required for this install to complete could not be run."You also noticed that RSOP.MSC and drag and drop of files did not work correctly.Copy and paste of files worked fine.

CAUSE: BackupExec requires a user level account be added to Default DCOM Security.Creating this account causes the "DefaultAccessPermission" value to be created.Removing the BackupExec DCOM entry does not seem to alter the "DefaultAccessPermission" in any way.

RESOLUTION: We removed the "DefaultAccessPermission" registry value (which does not exist by default) from the HKey_Local_Machine\Software\Microsoft\Ole Registry branch.Removing this entry also resolved the RSOP.MSC and Drag&Drop issue

The tech at Sunbelt said that BackupExec is known to register that key.  Since BackupExec is not installed on this server, it must be something else.  The only thing other than Exchange is McAffeeGroupShield for Exchange and an HP array diag utility.  I checked some other servers and the key was there and it is also on my XP workstation. After deleting the key IHateSpam installed with no errors.

I think the error is completely misleading, but - I am THRILLED that it's fixed.