Small network with a Windows 2008 server and a half dozen Windows 7 PCs. The setup is fairly simple in that an executable file is run from a mapped network drive on the server. We can see the file, it launches ok, and the program runs fine for somewhere between 15-25 minutes, and then just kicks out. We simultaneously lose the network connection, which is the root of the problem. Typically going into Computer and clicking the mapped drive brings it back, and then the program can be launched again to follow the same pattern. It is annoying because everything works fine for a while.