Recompiling Old Maps?

4 years ago, in a class, I made a really bad map called arena_island. Dispite how bad it was, one student in the class saved it, went on to teach the next year, and brought the map with him. He felt very close to this map. Recently, in the last update, the map will no longer run. I do not have the original hammer files, as it was 4 years ago, and I was much younger, so would there be a way to decompile the map file using an old version of a decompiler? I tried a couple different programs, but nothing seemed to work. If not, then I would have to remake the entire map from scratch tomorrow. (We need it for wednesday, where there is a "TF2 Tournoment".)

it would be good if I could get a response before 10 AM Wednesday PST.

I have, but it wouldn't work. the map file wasn't corrupt, either, since noone who had it downloaded on their computer could open it. It doesn't really matter now, because I remade it last night, but it would be nice if I could download an older version of BSPSource or something.