Update: The patch has gone live.
Original: Those playing the PlayStation 3 version of Call of Duty: Modern Warfare 2 may have experienced a few bugs, mainly the issue with party invites. Fortunately, Infinity Ward will be releasing a patch due out by this Friday.
A patch updating the trophies in the PS3 version will also be released shortly. There’s been no date announced, but shortly, none the less.
Patience is a virtue.