Look at the mtgox price now it's up to $6.50 usd per bitcoin! What's the explanation for the sudden increase in price?

I'm getting a massive amount of rejected shares on many mining pools when using Phoenix-1.7.3. When turning on -v debugging it shows the reason for  rejection is due to unknown-work??

I already did a search of this problem and found this link. However, it's unclear to me what the real problem is. The rejection rate I'm seeing when I mine on say abcpool.co and simplecoin.us, I get like 90%+ rejection(eg. 2 accepts, 13 rejects). This doesn't happen when I use ufaminer. Oddly, bitcoinpool.com seems to be okay with phoenix.

Why does this happen and is there a way to fix this? I would have posted this on that thread I linked but since I'm a newbie, the forum won't allow me so I'm posting it here instead.

Thanks