Well here's my case.
I have two pcs connected in a WLAN. PC1 has its wireless connection bridged with a ethernet connection to a dsl router so as to have internet on PC2.
However, even if Internet works fine there's no way to ping PC2 from PC1 or PC1 from PC2(100% packets lost). As a matter of fact, I cannot even share its resources (It gives me the network path not found error and you dont have the sufficient rights) Anyway, I can see from PC2 the Pc1 from mshome workgroup whereas from pc1 i cannot even access the workgroup. I have disabled all kind of router or desktop firewalls. It's also mentionable that when I disable the bridge and connect only with wireless networks everything works fine (sharing etc.) but when i disable ethernet connection with router in my bridged connection (which seems pretty much the same thing) i get the same error.
p.s. all ips seems fine and router configuration is flawlessly set.

Thanks in advance.

just a thought try running File & print sharing on both PC's again (mainly PC1 & be shure of correct Workgroup Name).
MORE info needed, what model router are you using config of LAN access could be restricting sharing.

I've always found it impossible to file share accross a bridged connection. Something about not being able to fileshare accross Internet Conection Sharing going all the way back to win 9x.