Weird Problem with windows network

Ok well I am using a Linksys WRT54G Wireless router. And I set up a home network and got everything connected (all my backup drives and such connected to the network) and I have a printer plugged into my moms computer. That is the main fileserver and print server of the house. The weird thing is, when my moms computer is connected to the router wirelesly only the wireless computers can connect to the backup hard drive and the printer. But when its connected via cat-5 cable only the computers that are connected to the router via cat-5 can only view the backup hard drive and printer on her computer. Does anyone know why it would be doing this? Thank you.

What firmware are you using on your router? I'm not too sure about the stock firmware, but with the Sveasoft firmware theres an option "AP Isolation" which makes it impossible for the wireless clients to acsess the wired clients. This is useful for extra security, so if someone hacks ur wireless, they can't acsess any of your wired computers. Try going through the advanced settings for something like that.