So many socket connections in FIN_WAIT_1 state

Hello,

I have unique problem.. we have third party streaming
server application for mobiles (its a CDMA network).. that
streams video content to mobile..
It was running fine but
After applying security patch (hotfix KB823980) this
application started taking 100% CPU ...
when i investigated the problem .. i found that
there are lot many TCP Connections remain in FIN_WAIT_1
state and so the Application has to go through all the
connections while establishing a new socket for a new user
hence taking more CPU ..
Its a real time application..
Since Application is closing the socket properly .. and
connections are in the FIN_WAIT_1 state .. its
responsibiliy of OS to clean up the connections ( it seems
from the system that connections are not timing out in
FIN_WAIT_1 state).. I suspect the security patch has done
something wrong with the TCP/IP Implementation on OS.. But
i am not able to figure out the exact problem...

Can anybody throw some light on this..

We have 11 Windows 2000 advance server running with
streaming application.. all are load balanced by NLBS ..FYI

Regards
Ankur