I have been setting up a wireless home network and could not get one of the pcs - XP Home SP2 - onto the network.
I have been getting the error message "Workgroup not accessible, you may not have permission to use this network resource" for ages and could not get this machine any further. I had searched many websites for help. I followed this link from Bill and worked through the suggestions. I discovered it mentioned pc-cillin as a possible cause, it came on my system disk. I uninstalled it and my problem was fixed instantly - I can now see all the machines on my wireless network.
Thought this information might be useful, and thank you for restoring my sanity.