Mail crashes with Mountain Lion

Question

Everytime I go to launch Mail it crashes with the following error
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libsystem_c.dylib                  0x00007fff89dbb690 strlen + 16
This is really bad because I have discovered that iCloud does not have a number of folders that were supposedly on iCloud according to Mail and of course anything that was stored On My Mac is not there either.  I am presently using Postbox which is fine but not optimal since I use Mail otherwise.
I tried restoring Mail from Time Machine and that did not work, and all of the repair database instructions I can find are either out of date or require that Mail actually be running to work.  The problem is unique to my Mac Pro, my other Macs work fine.
The Mac Pro is my primary machine.  Is there a way to restore an old mail database and force it to rebuild?
Do I need to reinstall Mountain Lion?
Need some guidance friends.
Ross

Answer 1

Miraculously, the post below about Lion works for Mountain Lion as well. 
https://discussions.apple.com/message/17011733#17011733
macmrjohn   Re: Mail 5 (OSX Lion) does not work after mailbox migration     Dec 15, 2011 1:43 PM    (in response to Alejandro M. Ramallo)  This same thing happened today when migrating a friend's laptop. THE SOLUTION: Inside the Library folder (Lion hides this folder now, so hold down the option key and use the Go menu in the finder — Library will appear in the menu. Go there.) you'll find the Mail folder. Inside the mail folder was another folder called V2. I simply took the contents of V2 and dragged them to the parent folder (Mail). When I launched mail again, everything was back to normal. As Apple says, "It's that simple!"