From another thread: you patched your tube, but the patch leaks? It wouldn't stick properly (or at all)?
I had a few patches that wouldn't stick. Then I learned to clean the tube around the puncture with alcohol, and since then, all patches lasted forever. If you don't have a little bottle with alcohol with you while riding, a solution might be a little packed wet tovel (like those you get in the plane). Make sure the area around the puncture is perfectly dry and, above all, without grease. Any amount of grease or dust will cause the patch not to stick.
Also, remember to wait for the glue (or "cement") to dry, before placing the patch over it, and then push on it like you're possessed.