It's normal for svchost.exe -k DcomLaunch to be at the system integrity level. (Dopusx64.exe should still be at medium level, though.)
Another thing which might cause Opus's Admin buttons to be disabled is if Opus is being run in XP (or earlier) compatibility mode, so it looks to Opus like it is running on XP (or earlier) and not Vista or Win7. (To check that, go to the Compatibility tab shown at the bottom of the FAQ and make sure all the other checkboxes are also off.)
If you go to C:\Program Files and create a new folder, does Opus successfully trigger a UAC prompt? Or does it succeed without prompt, or simply fail?
Have you tried reinstalling Opus? Just install it over the top of itself in case re-registering its components helps. (Don't uninstall first as it will erase your config; or if you do want to uninstall, do a config backup first.)