Here's the game I think I was thinking of: Lunar LockoutLUNAR LOCKOUT
http://www.funagain.com/control/product?product_id=010971&reviews_show_all=Y
Here's how one of the reviews describes it:
This is a great little solitaire game. It's quite similar to Ricochet Robot in theme, but there are some important differences. There are no walls--not even around the edges. You must get your man to the center solely by bouncing him off robots. The goal-spot is always the red square in the center. Instead of random board and piece placement, you must solve puzzles as provided on cards. If you think these differences would make it more simple than Ricochet Robot, then you're in for a big surprise. The puzzles, especially at the top levels, are tear-your-hair-out difficult. Solutions are thankfully provided on the backs of the cards, but that's cheating. The components are very high quality. The robots all have their own 'look' beyond being different colors. The base of the board slides out nicely, has storage space for the robots and cards, and snaps together snugly. My only complaint is that I'd like to see an expansion set soon with new puzzles to solve.