1) Make sure you have long range jumps researched
2) Move your ships to the star
3) with them selected, tell them to move to another star
4) wait while they jump
It is that easy....
If I could give negative kharma, I think this might be the time. By very nature, bugs don't do what they're supposed to. My guess is that since the wormhole is instantaneous it hoses up the calculation.
Let me say it again . . .
1) Every researchable item was researched.
2) Ships were at the star.
3) They were selected, then using move or the right click, the other star was set as the destination.
4) I waited while they scurried across the system they were in and used the wormhole instead.