Maybe less time typing on the innernet and more time process of elimination would be more productive towards sorting the problem. I'm not trying to be snide, sometimes comes a point you got take that bull by the horns. Anyone hearing a similar phenom who stumbles upon this thread might benefit from your efforts, both discussing and hands-on.
It's been an interesting thread here, something to read when traffic is slow. I hope you get it sorted out. Keep us informed of your progress.