Quit PT and trash your PT prefs (see digi OSX setup thread at the top of DUC for info) and then launch ProTools from the dock (NOT the session's PT icon) - create a new, blank ProTools session, then import all your tracks from the old corrupted session into this new happy session. using the 'import session data' command will ensure that all your automation and plug-ins come along with the imported audio tracks - if you want to avoid rewire, don't import the tracks that had the rewire plug-in on them. No need to panic, you'll be up and running again in no time.