The bolts on most of them I've ran across are bent in the middle from too many years of folks overtightening them.  Try cutting it in the gap of the clamp with a hacksaw, then putting the clamp in a vice and pull the bolt out from each end.

If it comes down to needing a new clamp, I've got a bunch of them.  You can have one free if you come get it, or if you make it to the meeting tomorrow night, I'll bring you one.

I will bring my light with me Monday night if we can replace the clamp on the resturant lot. God only knows where your Ing.timing is . You don`t want to melt your engine down over a 10cent bolt.