Workgroup Issues

I have dsl, 3 computers behind a router/firewall.
1 has windows xp pro, the other 2 have xp home edition. I can ping all computers on the network by ip address and hostname with each computer. Each computer has a shared folder. The only problem is with the xp pro machine. The xp pro can map to network drives and access them, but the xp home machines cant access my shared folder. They can see me, but they just dont have access to it.

Once, I think when i tried to map to the xp pro machines folder, i typed in \\devry\shared (shared folder). It asked for a login

? Should i just try to create a different workgroup ?

What are the requirements for this workgroup to work…