Thanks, going to play bracketing this weekend.

Quote - @viper...looks like you've got your answer...using one RAW with changed exposures will give you a "pseudo" HDR with progs like Photomatix...obviously CS2 doesn't like it.

In any event, if you want to get the best dynamic range you will need to bracket your RAW's with the cam...then create your HDR from that bracketted series.