I believe its an even older version from october 1999. I've never used alpha blending so I really didn't have any problems when using a lot of sprites.

Your sample didn't work for me either. The exe didn't seem to freeze when using hardware mode, its just that the square didn't fade in/out anymore. Odd enough the fps was even lower than my sample. Around 320 fps using hardware mode.

In any case, from what you've written, I'd say there's something wrong with your undelphix version.