Server :: Gphoto2 Cannot Run Correctly From A Php Script?

I recently discovered gphoto2 as an alternative to commercial PTP/Camera Control software. I'm tasked with designing a photo-booth kiosk for several museums. My intention is to front-end the thing with an adobe air gui. The gui will call scripts to operate the camera through gphoto2, and since the endpoint of the photos is an emailed message, I thought mysql/php would be appropriate.

The problem is this: gphoto2 cannot run correctly from a php script. I immediately realized the need to allow the www-data user access to the usb camera, and so I added www-user to the plugdev group.

As it stands, I can run gphoto2 like so:

Code:
sudo su www-data -c 'gphoto2 --capture-image'
even:
Code:
$sudo su www-data
$php -r 'echo exec("gphoto2 --capture-image");'

[Code]....