If you install 09-014 KB963027 Microsoft Security Bulletin MS09-014 - Critical: Cumulative Security Update for Internet Explorer (963027):
http://www.microsoft.com/technet/security/Bulletin/MS09-014.mspx which is this month's IE bulletin... you will see the following on your SBS box when you browse to Companyweb:

The trigger is NOT having installed KB961143

The issue is caused by the IE security patch.  To fix it install 961143 

Error message when you use Internet Explorer 8 Beta to access your company Web site in Windows Small Business Server 2003: "HTTP 401.1 - Unauthorized":
http://support.microsoft.com/kb/961143

Which is on MU but in the middle section

Install that, it doesn't even need a reboot

And Companyweb works

THANK YOU to Lars for the heads up on this issue