Error stating that I'm running an older version of Mail with a newer version of Mac OS X
You can go to Apples web site and download the updates manually. The downloads site is:

http://support.apple.com/downloads/

Once there, go to the "Search Downloads" "10.6.8" update. You can download either the combo (for people who haven't updated much) or the last, which was just for the 10.6.7 to 10.6.8. You might want to find specifically which update made the changes.

What I would try is the following:


Move Mail.app back to /Applications
Perform the manual update(s) from the downloaded update


IF the download allows you to go through the packages and you can find out which package mail is in (the names aren't always straight forward) you could probably do a manual update using only that package.

This might be risky, but you could try actually doing the full update on the system. In the PAST, you could do that and it would ignore any updates that superseded what's in the package or already installed and only install those components needing update. I don't write Apple's update software so that might be risky.

Hope this helps.