Also, in view/wizard.php line #1 uses a shortcode, if you have shortcodes disabled it’s not pretty.
OK I worked it out. In my theme I was fiddling with post content before wp_head() was called. Thus flowplayer_head() was being called after the shortcode was processed. The PLAYER const is set in the flowplayer_head function. Maybe you need a check to make sure flowplayer_head is always run before the shortcode is processed and not rely on wp_head to do setup stuff.