XP losses network with offline enabled

[Simon Angel]

I have a small network with several laptops. These have
offline files enabled and for the most part the settings
are default. When people are connected to the network and
working for a while the laptop appears to loose network
connectivity and they cannpot see any printers. If they
force a syncronisation then they are fine for a while.

How can I control XP's ability to detect whether it is
attached to the network?

Any ideas appreciated
Simon