Replace the neutral bus bar. They are available from electrical supply/building supply stores for not a lot of money.
Dollars to donuts you had a loose (hence high resistance) connection on one of the righthand wires, which led to the heating and burning you see evidence of.
If you have enough wire to get past the heat damaged bits, cut the bad off when installing the new bus bar. If you don't have enough, do whatever it takes to safely get enough--possibly running a new wire from somewhere convenient, maybe adding a box nearby to splice in a piece of wire.
I suspect your converter will work again once the fried connections are properly repaired. It's probably not working because it's getting no power.
When you do your repairs, don't put two wires in the same bus bar hole as the factory did ("double-tapped neutral"). This isn't acceptable under the NEC, at least as of the 2002 revision, and probably (perhaps by reference) for longer. What's even more curious is that they had enough spaces on the bus bar to not need to double-tap, but did so anyway...
By the way, double-tapping the ground bus bar is usually acceptable, as it's not carrying current in normal use.
