Do you have a non-portable computer that could sit there and run TiVo Desktop (with a fixed IP address)? (You can have more than one computer running it on the same network, I've got 3, fixing to add a 4th, working with 2 S2 DTs, and 2 older S2s). Even just for a day or two and see if that makes a difference. (I'm suspicious of the laptop)
You could try getting the S2 to find what's in the computer's "My TiVo Recordings" folder, and seeing if it will transfer anything to itself.
If you haven't already, give both TiVos, and anything else that doesn't leave the house and log onto a different network, a fixed IP address, if you haven't already. Might help, can't hurt.
Your router can do wireless on 11 different channels, if I'm not mistaken.
Perhaps the one you're on now has become overcrowded by a neighbor's new router or something, so you can try changing to a different channel.
It's unlikely but certainly not impossible that the TiVo brand wireless adapter has developed problems. Try it on the Premiere.
The above steps are different things that you can try (except the fixed IP thing, that's mandatory), but they are not necessarily a list to be followed sequentially. Change one thing at a time.
