Hoople - 2:52 am on Jul 19, 2010 (gmt 0) [edited by: Hoople at 3:11 am (utc) on Jul 19, 2010]
There WAS a 'pre SP3' Microsoft Exchange 2007 specific hotfix to address this. What mostly triggers this is calendar meeting invites. Seems to have gone missing.
Primary alternative is to install Exchange 2007 Service Pack 3 (recently released).
Another option, for the brave is to edit the configuration files to effect a change to how retry behaves. Generally a manual configuration edit may have negative performance implications post SPx where x is an number one greater that the first service pack effecting the fix. Second hit (TechNet) for 'exchange 2007 glitch retry interval'
I've been an Exchange guys since 5.5, the SP is the safest choice (most regression testing).
[edited by: Hoople at 3:11 am (utc) on Jul 19, 2010]