the backticks tell the SQL engine that the word contained within is a literal (e.g., the name of a field or table) and not a keyword or command. it usually makes no difference whatsoever if you use them or not, but it does prevent conflicts -and makes your sql more forward-compatible.
in this particular case, I'm not sure why it made the difference. it really shouldn't have. but hey, you don't argue with success...! :D
