I use a similar setup, Duet wired from Router that my laptop serves and is controlled by ipeng software via wifi from an ipod touch. So some little box somewhere on the new laptop is checked off when it shouldn't be or the other way around....I feel your pain!! ...OK check the forums if there are any for your specific app on the ipod. Ask the same question over at the forums logitech/squeezebox support has...I'll dig up the link for ya.
Does Squeezepad have a settings menu you can access from the ipod touch?? If yes, look in there for anything that may present a clue, opening a specific "port" etc... and tell us what you can about things in that that can be changed....gotta start somewhere.
Have you rerun the install or setup part of the SB Touch?? I would think something in there would help you out.......looking for the forum link....