HELP! HELP!

I'm losing my mind with this mod. I have managed to set up the cronjob, it runs and I get not errors in my email. However, the rates don't update? I've tried to change to root path over and over and followed many of the suggestions here but I just can't get it to work.

I have renamed catalog to shop. currency_update.php is in my shop file. It calls correctly and I do get the blank page if I run it in a browser. Any ideas?

Thank you!