PC to PC

I can't link up my XP to my Vista Home Premium computer. All service packs installed. Each computer can see the other but I can't access the XP's shared folder. I am using cross over USB cable and have installed drivers for same.

I get message trying to access my XP from my Vista pc - "folder is not accessible. You may not have permission to use this network resource." "Not enough server storage to process this command"

I have granted access on the XP to share this folder.

Is there a simple, 1,2,3 step by step process to ensure that I have met all necessary criteria to make a pc to pc connection?

Many thanks