Ok, that clears up some issues with your configuration, but your DSL connection is stricly IP unless you are doing AppleTalk over Ethernet and connection remotely to an AppleTalk IP server or peer that is sharing over IP. In other words, there is no reason to have your AppleTalk connection directed to your Ethernet unless you are actively using AppleTalk IP service via your DSL connection.
I don't recall the 360's port complement, but if I recall it should have what appears to be a normal 8-pin serial connection. If that printer communicates via AppleTalk, get an 8-pin serial cable that fits both your printer port and the port on the computer, then switch AppleTalk over to the port you want to use and see if the computer can see it over AppleTalk.
If I have the time I will check out the AppleSpec database and see if you are using a postscript printer or if the printer is dumb and needs system drivers.
In the meantime, direct Appletalk away from your Ethernet connection and see how your Internet services react.