What about downloading a combo update of Mac OS X 10.4.11 (if that is the version you want to have) and see if it reinstalls Mail. I haven't found any Mail 2.x installer around the usual sites, but maybe you can find one.
i dont even know where i would start to look for that?
Google "Pacifist OS X" and use that to install just Mail.app.
do i need the cd to do that?