mail application in osx 10.6 is damaged

Hello,

what has happen is, that my girlfriend went into my mail. And to not leave marks, she tried to delete the history in finder about visting my mail.

She tried to delete the mail application, and while being in the trash, she couldnt delete since the mail app still was in use. So se choosed to put it back and restart the computer..

Now the problem is, that everytime I try to open the mail application, it says mail application in osx is damaged..

What ive tried.

Verify permission and repair them NO-GO

Deleted the envelope index file and restarted NO-GO

What can I try more?

boot up on my snow leopard cd, and try to rebuild the system?