The level is shown as unsolved, although all balls are placed. Is there one outside the visible area?
Sounds like a bug. I will look into it.
The box at the top left (on goal) is out of the playable area. All you need to do is remove it (replace it with blank or wall) in your slc file (opened with Wordpad). You will not be able to see this box in the game.
@Mark: found it! Thanks a lot!