Linking wireless network into wired LAN

Can anybody help me?
I have set up 10 PCs on a wired LAN (Which works fine.)and I recently linked up a remote PC with a wireless network card. The problem I have is that the two PCs that are linked using the wireless cards are able to see each other no problem, but the PC that is remote to the wired LAN cannot see any other PCson the wired LAN, and vice versa. I am running WIN98SE on all machines except for the server which runs WINNT4 Workstation. Both PCs that use the wireless cards run WIN98SE. I have installed the Access Point software to see the network as per manual but with no joy. The Supplier of the wireless cards and software is Zoom Air. Anybody familiar with this product?
Any advice would be gratefully received.
Thanks.