OK...it *was* my ISP. We had to hard code my IP address instead of letting Windows find it automatically.
After that, I was able to log on anywhere and teleport anywhere....but now my husband can't get online anywhere, at all, and he's none too pleased. No return call from the ISP yet on how to resolve this. I suspect I just need to get him back in the network, but I have no idea how this is done with Vista.
If it ain't one thang....