@strung - I have already tried most of these & the ones i didn't try did not help.
I have spoken to many exchange guru's on this and apparently this is a known problem with MAC's installer. It is very dicy and does not seem to have specific fix. What has worked with some folks has not (in the same environment) with others.
I fixed mine by starting over (for the 5th time) uninstalling/reinstalling Office 2k8. Although, i disabled ESET Nod32 Beta for MAC - i uninstalled it this time around (not sure if it had any barring yet or not). I applied *ONLY* two patches 10.2.3 & 10.2.4. Rebooted, then downloaded Netopia's newest EWS (13.0.4), which installed successfully! I also never opened Entourage 2k8 the entire install time period until EWS was finished successfully.
http://www.microsoft.com/mac/downloads.mspx?pid=Mactopia_Office2008&fid=540B4901-8CAC-481C-936C-E56C60CA79C6#viewer