When deploying a Drupal site on a shared hosting environment running apache/php, chances are php’s safe mode is turned on.
If you’re trying to get flashvideo up and running, you’ll probably run into a problem when Drupal’s cron job tries to run ffmpeg to convert your uploaded video:
“Cannot execute using backquotes in Safe Mode”
Solution: turn off safe mode by modifying your httpd.conf file:
1. find your vhost entry
2. add to that vhost entry: php_admin_flag safe_mode Off
Problem solved.