Hi Joe,
As I searched and read all the related topics about screenshot, I solved this problem.
Here is how I successfully done the screen capture on PSR-S670:
1) download and install SendSX;
2) connect S670 with cable to computer, and connect USB flash drive to S670
3) open SendSX, set MIDI IN/OUT to S670;
4) in the MIDI OUT field, the following is the correct info should be typed:
F0 43 73 01 51 09 00 00 00 F7
F0 43 73 01 51 09 00 02 01 04 F7
5) press send and you can hear treebell rings, capture complete. Connect USB flash drive to computer and you will find CAPT000.BMP etc.
So I think the sysex you provide here might not be right. The above sysex I used is found in your post here:http://www.psrtutorial.com/forum/index.php/topic,23546.0.html