NetBIOS in Windows98

Hi,

I have a problem with the NetBIOS Protocol.when I try to
map a shared drive of a machine from a win2k machine, It
is getting mapped and when I disconnect the mapped drive,
The win2k(client) machine on receiving the response for
the disconnect message send the FIN/ACk to close the TCP-
139 connection.
But when I try to map a drive from win98(client)
then , when trying to disconnect then even though the
response is received by the win98 client, The FIN/ACK is
not sent by the client, because of which the TCP-139
connection is still open. And the client is sending TCP
RST after arund 15 minutes.

Is it required to cahnge any system settings to make
win98 send back FIN/ACK as soon as the response is
received when trying to disconnect the map drive, as done
by win2k machines.
Please suggest me a solution.
Thanks in Advance.

-Saritha