Okay, I misread your earlier thread so thought you were talking about cup on left side, we are in fact talking about fixed cup on right side.
http://www.bikeforums.net/showthread.......-Which-one.
Which way are you turning the cup? The right hand side is reverse threaded so you need to be turning counterclockwise.Perhaps its jammed in from attempts to turn in wrong direction? Otherwise best guess is that when you screwed in, the cup wasn't straight so went in a bit crooked and jammed. Anyway, I think more info is needed about how exactly you attempted to install the cup to determine next steps.