Is it possible for me to register a DLL or EXE (COM) on a dreamhost server?
On a shared server? Very doubtful.
Typically registering a DLL or EXE file on the server is reserved for windows machines as far as I am aware.
Seeing as Dreamhost hosts their sites on what seems to be Linux machines I don’t think it will be possible to do so. I would contact tech support directly about it at email@example.com