I believe that there's an error with your user's setup. It seems everthing is in working order.
However, you should do a few final steps before contacting support. First off put this at the top of your cron file
This will send any error messages you might be getting to your E-mail address. Also, make sure there is at least one blank line at the bottom of your cron file. With these things in place, and if you're sure it's not running - then contact support.
On a side note, there's a easier way to get your commands to run every 15 min besides putting in a new entry. for instance:
*/15 * * * * /usr/bin/perl ....
Will run your command every 15 min. You can also list min if you'd prefer:
2,8,29,45,51 * * * *
Same goes for all the other fields, if you want specific days or whatever.