Which website spread are you refering to?
He would be referring to the MtGox/TH spread: According to bitcoincharts, $2.51 versus $2.39. Huge difference that no one seems to be taking advantage of. I would suggest TH is having technical problems at the moment.
No problem that I'm aware of (except that they did not process my wire deposit request on schedule again.) I've been trading all day with not problems.
The answer is rather obvious. It 'problem' comes and goes and has been doing so for weeks (if not months) which anyone paying attention would know. There is simply not enough people with funds in Tradehill who are willing to buy at the prices that people are on Mt. Gox. There has been a much higher supply on Tradehill for at least a few weeks (possibly the haul from a theft) and it takes a lot of interest to dig through it. The handful of people doing arbitrage burnt out and need time to replenish their funds. You don't have to make this a harder problem than it is.