On the V3 select OTHERS at the connect PLAYMATE? menu.
When both say Stand-By, point the tops together and press the B (middle) button on one of them.
Note: if that still doesn't work, do this on your V4 then try again: press the Reset button on the back, then select Download from the Download / Reset menu that appears on the screen.
As binary said select others. You may need to clear some of the friends on your list too. I hope your tama can connect soon, try connecting the V4 to a V4 and the V3 to a V3. Mine done that before so I had to get a new battery.