This can happen if you have another router within your network that is not UDP compatible.
Also check to make sure the wireless adapter on the computer is primary.
In windows vista:
Open Network & Sharing by clicking once on the network icon in the right corner down by the clock.
Now click on Manage Network Connections from the Links on the left menu.
Go to the Advanced Menu, and select advanced settings.
From the connections area, move your wireless network adapter to the top of the list.
Press ok, and ok again.
Since you are using wireless network on the laptop you want wireless to be primary.
Most program will send/receive from which ever adapter is first and then try each adapter from there.