I'm trying to share files on three computers. Mine is hardwired to a wrt54g v6, and the other two are wireless. The other two computers can "see" each other (and me) on the network and access each others shared folders but when they try to access mine, they get an error saying that they don't have permission to. I can see both of them and their shared folders, and we all can get to the internet. File and printer sharing is enabled on all three, with no firewall other than MS. And (yes) we are all in the same workgroup.
When I first set it up 2 weeks ago, I upgraded to the latest firmware it worked fine. It's only been a few days since it screwed up, and I've been going crazy trying to repair it.
MORE INFO: They can still print to my printer, and I can still host Diablo 2 when my son and I game.