launching HandBrakeCLI from a controller

[eluser]pdxbenjamin[/eluser]
Hi Everyon,

I'm using this to launch HandBrakeCLI from within my controller.
exec("HandBrakeCLI --preset "iPhone & iPod Touch" --vb 200 --width 320 --two-pass --turbo --optimize --input pr6.dv --output pr6.mp4")

The string is from this site where i'm trying my hand at some html5 video.
http://diveintohtml5.org/video.html

When I run this script from the actual command line, it works perfectly. I run HandBrakeCLI from /usr/bin/

I have other lines in my script running exec as well, to do the ffmpeg portion and they are working fine.
exec("/srv/scripts/ffmpeg2theora-0.27.linux64.bin --videobitrate 200 --max_size 320x240 ".$path.$inboxfile." --output ".$path.$outboxdv."");

When I append /usr/bin to my original exec in the php script much like the ffmpeg to achieve an absolute path the script dies all together.
exec("/usr/bin/HandBrakeCLI --preset "iPhone & iPod Touch" --vb 200 --width 320 --two-pass --turbo --optimize --input pr6.dv --output pr6.mp4")


Can anyone help, and tell me why I can't absolute path launching HandBrakeCLI from controller?