It looks like the issue is that your computer and iPod each have internal IP addresses on different sub-nets, which usually means that they are connecting to different routers. Do you have more than one router on your network? If so, then what's most likely happening is that each router is creating its own internal sub-network, and devices on one subnetwork are not able to connect to ones on another sub-network.
What are the make and models of your routers, and how are they connected to each other, your devices, and your cable or DSL modem?
