Office Professional 2010 Key Entourage OWA keeps

Two or three weeks ago we've got started encountering an frustrating and
inexplicable condition the place Entourage customers would out of the blue be
disconnected from Exchange. However, OWA also wouldn't give good results,Microsoft Office Ultimate 2007, but MS
Outlook continued to work fine.
Due to MAPi nevertheless working I'm guessing this has something to perform IIS,Office Professional Plus 2007,
but you can find small to help this with the logs and what the trigger is.
Only issue I can find is while in the Applications log as follows :-
"
17:05:29 Faulting software inetinfo.exe, edition six.0.3790.1830,
faulting module TransportScan.dll, edition six.0.1148.0,Microsoft Office 2010 Pro, fault tackle
0x00002eb4
17:07:01 Reporting queued error: faulting application w3wp.exe, edition
six.0.3790.1830, faulting module davex.dll, edition 6.5.7638.one, fault
handle 0x0005dfcd
"
What we are being informed is usually that IIS has to be re-installed however
the process shouldn't be as relatively easy as running the installer yet again. It
usually requires backing up Exchange,Microsoft Office Professional 2007, de-installing Exchange, re-installing
IIS,Office Professional 2010 Key, re-installing Exchange and restoring mailboxes.
I am reluctant to move forward with no knowinginvestigating about any
difficulties to our 90 Entourage/3 Outlook consumers and their electronic mail, calendars,
delegated calendaring, and so on.
Does any individual have any practical knowledge of a re-install and can advise to the
process?
Server: Windows Enterprise Server 2003 SP2, Exchange 2003 SP.
Also runs Symantec Backup Exec ten.x, McAfee AntiVirus, McAfee
GroupShield.
Kind regards
Craig.