Word 2k lockups local machine on LAN

Greetings:
There are 2 machines on a client’s small LAN that will lockup when saving & or deleting Word 2000 documents to network shares (the LAN has a functioning gateway to the Internet), no other client machines are affected. Access and Excell (Office 2000) files work fine, and the workstations and network are virus free. All the network shares reside on an IBM Netfinity 5000 server, running NT 4.0 SBS with service pack 6. Please point me in the right direction as to where the fix may be found.