As he said, he was mistaken. In point of fact, there are several things that are added via the onload event. That's not where the problem is.
I don't *know* it is in motools.js, but that compression code is pretty generic and it is being invoked from motools.js line 21 at the point the failure occurs. At least, that's what I got out of FireBug's stack trace.
An optimist sees the glass as half full.
A pessimist sees the glass as half empty.
A realist drinks it no matter how much there is.