The Exorcism spell in fact does still work, although its usefulness has been diminished by the Publish 59 addition of the auto-removal of corpse-less ghosts from champion spawn regions which triggers periodically. My assumption is that the player that you spoke to more than likely still had a corpse in the region.
As far as your odd karma gain, I have been unable to reproduce this result. When my karma has been locked, I am only seeing negative karma gains. Can you elaborate on what may have recently occurred or if you had done anything unusual?