Delayed Write Failed-unable to save

I am having a problem with our VPN. When a PC at our remote site tries to save a file to a server in the home office they get the following message:
“Windows-Delayed Write Failed” “Windows was unable to save all the data for the file\device\lanmanredirector\servername\Admin\filename”
The remote office is a peer to peer network (6 PCs) with 98 and 2000 PCs. The VPN had worked fine until I added an additional 2000 PC and then they started to get the above message.
Can anyone shed some light on this?
Thanks,
Mike Peck