interesting. Can you let me know which version of flash and safari are you using so i can have a look?
For some odd reason only safari makes problems. It was such an headache to already get the facebook integration because of their weird javascript handling policies... ;-)
I'm having difficulty reproducing the issue, though. The videos weren't loading either, so it's possible that clicking the close-box while buffering the tutorial video created a race condition or something. I hope that helps.