XP connection limit — dropped mapped drives

You can configure the AutoDisconnect time by running the following command from a command prompt:

net config server /autodisconnect:time_before_autodisconnect

Specify the time in minutes.

http://support.microsoft.com/kb/314882

Or, I found this:

I had the same problems (Dropped drives, workstations disconnecting, ect.) and could not find a solution anywhere. But I finally did find an answer. Try one of the following or both:

[To turn Autodisconnect off] Type > net config server /autodisconnect:-1
[Try this on the server and ws]

or

Install or repair the DHCP, DNS and WINS on the server. Setting up theses services “correctly” Completely! solved the problem. I did them all at once so I am not sure which one was the trick but I suspect WINS was the key.