One of the great things about working on the Flex development team is seeing how people create these amazing applications; things you never would have thought possible. However, the flip side of that is that when people are developing things you never would have thought possible, they get errors you never would have thought possible. I have set up a wiki page to help track error codes and possible solutions. I update this page whenever I hear of a new one and I encourage you to do the same. So far, it just has runtime errors, but feel free to add compiler errors and warnings, too. At some point, we’ll harvest these and roll them into the docs.
Along the same lines, Judah Frangipane (perhaps better known as dorkie dork fromdorktown on flexcoders), has written a flex app that searches LiveDocs, his blog, and the Error Codes wiki page for a given error code. Give that a try, too!