Much as I recognize the possibility for abusing the system, even the fact that he was placing bets (If such is a fact) wouldn't necessarily mean he made incorrect calls. This would be doubly true if teams he officiated for are surprised by the claims, rather than saying "Yeah, we were gipped outta X victory by his lousy call, this explains a lot".

In short: He may well be a crooked bastard, but that doesn't invalidate every game he's been involved in.