Cant remove computers from scope

I have about 3 64bit OS computers that DC tried/did install when I was on version 6.1.16. I have now upgraded to 6.2, and I cannot remove the computers from the scope. If I try to "uninstall" them, I just get an error but their Agent Status stays as "installed successfully" so it never allows me to remove them.

Also, 64bit support would be really nice......