Using Windows named pipes between Win7 and XP

I have written a C application to run on a small wireless network (linksys router). The application uses named pipes. When the server is a Win 7 machine and the client is a XP (Pro, SP3) machine the named pipes connection works fine and the app runs perfectly. However, when I swap roles and make the server the XP machine and the client the Win 7 machine, the pipe fails.

I have tried turning off the firewall on the XP machine and that doesn't solve the problem.

File and print sharing between the two machines works fin开发者_如何学JAVAe.

Any suggestions would be most gratefully accepted.