NETGEAR ProSafe™ 802.11g Wireless VPN Firewall FVG318

I have 6 pc's and 2 Macs (just started changing everything to Macs). The pcs can see the macs on our network, but the Macs can't see the PC's. They are all hard-wired into the router -- but they cannot see them by Airport either.

Has anyone had this problem and know how to fix it? We have had the iMacs for a little over 6 months now. I have not had a Mac before, and my staff loves them other than this problem! Hopefully someone can help me!

Here is their configuration:

IMAC 27"/4850-512MB
2.8GHZ QUAD-CORE INTEL CORE I7
4GB 1066MHZ DDR3 SDRAM - 2X2GB
1TB SERIAL ATA DRIVE
ATI RADEON HD 4850 512MB
8X DOUBLE-LAYER SUPERDRIVE
APPLE MAGIC MOUSE
WL KYBD & USER'S GUIDE
COUNTRY KIT,IMAC 27-INCH

The Network is listed above: NETGEAR ProSafe™ 802.11g Wireless VPN Firewall FVG318

I have tried resetting the Network, resetting the network settings on the Macs -- everything I know how to do. Any suggestions, please?