Fixing Punctures / Puncture Repair / Exploding Tubes

I've just finished patching up an old inner tube & upon fitting the tube and tire to the wheel i noticed a slow leek of air. I took out the inner tube again to realize that I'd punctured my tube when i was prying the clinchers on. Accidentally pinching the tube against the rim.

Back to square one.

Has anyone here had similar problems?

really?

common problem.

after fitting the tyre onto the rim, go around the wheel and check that the inner tube isnt caught anywhere and is properly seated.