...weird stuff happens when you fiddle a lot with the various parameters. You need to do a LOT of experimenting to find the best settings for your needs.

I also found that outputting at BEST QUALITY crashed my WinXP machine (not a drastic crash- but needed to re-boot and PhotoShop would not work, etc.)- so AVOID that setting- probably requires a TON of RAM to be happy, I suspect... you don't really need it anyway- (at least not for my purposes...)