Can ping, cannot get to shared folders

Hi all.
My first post here, will try to keep it short and informative. I have Airlink101 w325 router, two wired computers (a desktop and a laptop), 2 wireless laptops, 1 wireless PocketPC. All my computers connect to internet without any problem. They also can ping each other, no problem. But wireless devices cannot connect to the shared folders on the wired desktop. Wired laptop has no problem connecting to the same folders. I have turned off the windows firewall. The problem is that only wireless devices cannot reach the folders. Ping is very fast, by both the desktop name and ip address. All machines are in the same workgroup. Before Airlink I was using a netgear router and didn't have this problem.
There must be something in the wireless settings that doesn't allow laptops and pocketpc to connect to desktop. Airlink support was not supportive at all. They just blamed Microsoft. I told them Netgear worked fine, wired computers work fine, no luck. "Microsoft's fault".

I need your experience.
Thanks in advance,
David