Media Server Disconnect after 30 minutes

I had no problem configuring LnS to allow Tveristy to allow communication [streaming media] between my PC and a D-Link RSM520 [I allow "all" traffic to the MAC address.]
The issue is that after about 30 minutes I get disconnected. Routinely.
The Linksys router and RSM520 are fine as they play the entire movie when used via another PC or with LnS disabled.
LnS antiFlood is disabled.
Anyone else have a problem with streaming media?
Is there a better rule that I've overlooked?
Is this a trial mode issue?
[I note that DFragFAT.exe runs as a service just about when the disconnect occurs. I believe this is part of windows prefetch. Would this react with LnS? Or may be a coincident.]
Thanks for any comment.