I do not use RM, and try to avoid it all costs, so I really cant help much. The only thing I can offer is either the scripting is different with HTC and thats causing the error, or you might not have any permissions to fix. What led you to try fixing your permissions?
It's still stock 2.1, also the error message is " an error occured while running privlieged commands " ....the phone has superuser and Rom Manager has been authorized..