It is possible if there was no response at all you'd be getting nothing but request timed out messages from a simple ping attempt.
Honestly I've not dealt with simple ping requests in some time myself as all the networks and tools I've used recently have been fully windows compatible it's been easier to just use the gui for connecting.
I assume you've run 'ipconfig /all' and verified that the local data is the same for the laptop whether it's plugged in or on the wireless. this could be a simple translation issue between ipv4 and ipv6.
edit: it was ipv6 after all. Thanks for letting me know. I was actually about to fire up my laptop to try and reproduce your problem when I realized my lappy was still running xp.