Today I tried my luck compiling a custom XPCOM Component for XULRunner. The component wouldn't load, simply leaving an error in the console "Failed to load XPCOM component: ...."

I was having a terrible time debugging the problem and I couldn't seem to find the relevant documentation. Finally I asked for help on the #mozpad irc chat room. Plasticmillion pointed me to the correct document that I couldn't seem to find on google for whatever reason.

I'm posting this for future reference, and to hopefully give this link a little more "google juice" .... If you are having trouble with XPCOM registration, regxpcom, etc, this should help:
  Troubleshooting XPCOM components registration