command-tab dock issues

I am running a macbook pro with 10.6. After a fresh restart everything is fine. However immediately after opening mac mail the command-tab (spaces switching) and dock is no longer functioning. The dock simply disappears and will not pop back up. It has me stumped and I am inclined to try to erase and reinstall mac. I am hoping someone might have a suggestion before doing anything that drastic. Ideas anyone?

Try opening a terminal and typing
killall Dock
That should restart the Dock and hopefully bring it back.

Do you have something else loaded? Typically cmd-tab is application switching.

Yes

Yes I have other programs running in order to test the command-tab function. It is just really weird. Switching and dock is fine until I open mac mail. Then those two things quit working.