Ursula must be busy, but has already helped by providing the port test link in the signature above. Try that, and assuming it reports "Success!", then try sharing more files. Some people have had better success having their connections accepted if they share ~100 files.

Have you already read through the XP connections posts in the "Connections Problems" link?

cheers. Post back, and maybe someone who knows XP can help. The fact that you can connect at times but not others is odd. Does Compuserve only allow filesharing at certain times?