I had a similar problem with installing an AIR Help file. I was able to install and view other AIR Help files on the same PC, but every time I tried this one, it would fail with Error# 0. I eventually tried every version of that file I had generated, and they all failed. Then I realized they all had one thing in common...the Help ID. I changed the Help ID, and the file installed just fine.
FYI, I did search the registry for the corrupt Help ID, but it was not found. I'm not sure how to locate and remove this corrupt item, but at least I found a workaround.