Problem registering a dll - Access Denied

That error mostlikely comes up because you can't delete a corresponding .tlb file. Two other suggestions:

1. Stop IIS and attempt to register again:
2. Stop IIS, remove .tlb files from wherever your DLL file is and then attempt to register again.
3. Close all IE/IIS/DEV tools (they might be keeping some files in read-only state) and then attempt to register your DLL

The account under which you run regasm doesn't have rights to write to C:\Program Files\FooProg\ and that's why regasm fails to write the .tlb. Run regasm under an account with administrator priviledges.

The account you are using needs administrator privileges.