[popnbrown]

Can you provide us with a picture?

If you have wheels that spin against a ball, it should launch the ball. Unless it there's too much friction between the spinning wheels and the balls that the ball gets stuck on the wheels and starts spinning.
Depending on the type of wheel you are using the cloth of the ball might be getting stuck.

It would actually also help if you could put up a video of the system working.

From team history, we used a pretty big wheel maybe 8in in diameter to launch a squishy but completely solid ball (unfortunately, I don't know what type of the top of my head) in the 2006 game Aim High.

Your best option is probably to search chiefdelphi and thebluealliance.net to look for other shooter designs from the 2006 game.

If there are any other things that I can help you with PM me. I'll ask my team members who were involved with the 2006 robot, to give you some specifics if you would like.

Good Luck,
Sravan