Explorer constant refreshing within network places

I have a few people that connect thru a VPN and do all
their work over that connection. Now the problem is that
those that have Windows XP Pro get their folder-tree
constantly refreshed, it slows down the browsing between
the folders. All I know that its not the VPN thats causing
this constant refreshing because there are other people
that use Windows 2000 Pro that dont have this problem,
only those that use windows xp pro.

I have searched the webb for weeks with no results that
ended in this problem beeing solved. So I post here hoping
someone have some clue on what might be causing this
constant refreshing of the folder-tree.

I can see that its refreshing because the small hourglass
appears next to the pointer if you place it somewhere on
the folder-tree window. If I move the pointer to the file-
window the hourglass is not there.

This is a minor annoyance if you are trying to work and
windows xp refreshes the folder-tree constantly. Any help
is appreciated.