.mac won't recognize my password after 10.5.3

So after I updated my macbook and iMac, I go to sync with my .mac account.

The iMac works just fine with .mac and syncing; however, the macbook pops up "Unknown Validation Error. Your .Mac member name or password may be invalid. Please enter a different name or password."

I've reset my password and can still log into .mac through the iMac and I can even log into my .mac account through Safari on the macbook.

I spent 2 hours on the phone with applecare yesterday moving preference folders around and restarting a million times. Finally, applecare have be archive and reinstall 10.5.2. That worked fine and .mac was syncing beautifully. I was then told to update back up to 10.5.3 and now the same problem appears.

Suggestions? Help?

Thanks!

 

Also...

I forgot to mention that "back to my mac" works just fine on the macbook; however, iDisk doesn't work either.

Another call to Applecare resulted in a "sorry, I don't know what else to do." I've archived and installed AGAIN, and will live with 10.5.2 until someone has a better idea.

Help has to be out there somewhere.

Pretty please?