Save Frame Position ruins Frame

I decided to add a simple checkpoint system to my level. When you touch the checkpoint, it saves the frame position and deactivates. If you die and the checkpoint has been reached, it loads the frame position instead of resetting the frame.
But when it does this, a ton of completely baffling things go wrong:
-The score is copied and pasted into a layer below it.
-You can no longer shoot, but jumping still works.
-Ending the level results in an error.
-Some randomly chosen cannon traps designed to launch missiles every 2 seconds appear to have missiles stuck inside them, and there's an endless cacophony of explosion sound effects. Different cannons are affected each time, and sometimes none are affected at all.

Any suggestions?

Sorry I took so long to reply to all you guys! I had started a response a few days ago that got lost before I finished it, and haven't remembered to write another one until now. Hopefully someone is still willing to help.

So, about using an Array. I've never really used Arrays before, but I'm not sure how easy it would be to save all the important progress the player has made on a level. I can see how I could use one to store things like the player's position, score, and health, and in fact that was something like my original plan. The problem was coming up with a way to store which coins the player has collected so far, as they play a very important role in the game. Forcing the player to re-collect all of them after every death seemed a little harsh( though I might do that as a last resort if I can't get this to work), and allowing the player to keep every coin they collect before and after the checkpoint would allow them to get dangerously-placed coins without needing to survive the hazards.
Hmm... now that I think about it, would it be enough to just record the fixed value of every coin you collect, then destroy the coins with those fixed values every time the checkpoint resets the level? I wonder if that would work...

And I would be happy to try to reproduce this problem on something small enough to fit in a file to upload. It'll take some time, though.

Thanks for your advice everyone!