I suspect the problem may be that the NetGear is acting as a DHCP host for your internal PCs... In doing this your internal computers are assigned IP addresses that are not directly accessable from the net (192.168.X.X etc) ...I have a Lynksys that does a similar deal. In my case there is an option in the Lynksys to designate one port on the switch to be on the 'public' side of the system... in other words it would directly accessable from the net. If you configure the PC you want to share from to operate on that port then folks should be able to find you. You will probably need to refer to the owners manual (yeah I know I hate to do that too).

Then again I could be totally wrong -