server connection trouble please help

hey my girlfriend has a PC laptop that she has set up a server on and i have an imac, we have connected and played together a few times so i know it works but since then i have been getting this message oi.netty.channel.connectionTimeoutException: connection timed out:
my mac is running 10.6.8 if that helps.

thanks any replies would be much appreciated.

Sorry, I'm not sure how to help because everyone else can connect. I would assume it's something to do with her connection though.