Not running a firewall *bad I know :\* but my friend and I have exact same set ups: XP Pro, latest versions of Messenger as well as Plus!, and our systems are exactly the same except I have way more hard drive and ram than him
Both of us had the same thing: caused problems with messenger itself, would freeze up or sign us out completely, one or the other of us could only see the files but access when granted wouldn't work. Once we both uninstalled the plug in everything else returned to normal. Will wait for newer version of this to try again.