Did you have this problem four years ago? What kind of "charger" did you use?
It's possible that you fried the start switch, could be a solonoid somewhere on those things. You might try getting your hands on a wiring diagram and see where those cables lead and branch off into?
When I had the charger hooked up to the battery I have never had a problem, but I have heard horror stories from people that have gone direct from charger to cables with no battery in between... It's "possible" you did do some electrical damage, and judging from your story I would say that could be the case...