I could do with knowing more about the script and the environment in which it is to be executed. If its a permissions problem it shouldn't be fabulously difficult to resolve, however it may be an assortment of things.

How did you set the cron? Is the user used to set the cron in the cron group (assuming your on *nix)? What file permissions has the file got? Can it be run manually?

__________________
mysql> SELECT * FROM `users` WHERE `users`.`clue` > 0;
Empty set (0.00 sec)