problems with Windows synchronising files

I have Windows XP Professional Version 2002.
For some time I have used the synchronisation function quite happily between a desktop PC and 2 laptops over a Netgear wireless network. Recently I have noticed that one of the laptops (the one I use out of the office, not normally the one I use to originate files) is not updating properly – new folders arent available offline.
The sync process seems to be working normally. Any ideas about what might be wrong?