XP-pro XP-home networking problem

I have an XP-pro PC as the host and XP-home PC as client, on a peer-to-peer network. Earlier it was possible to access shared files on either PCs. However, recently the pro PC can access files on home PC, but home PC cannot access files on pro PC. The error message on home PC is “\\SYSTEM1\xxxx is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions. Not enough server storage is available to process this command.”

How do I solve this, please.