Hi,

I did encounter a similar problem previously. (ie, i can run the script manually, but it does not run in cron)

Perhaps you can try:
1. chmod the script, say try to allow all to read,write,exec ( i know its dangerous, but if it works, you can narrow it down to permission, maybe can try to chmod to 750, or something)
2.Set your environment. ( because when you log in to run manually, somehow the system knows that its you, but when you do it in cron, the system does not. I am not sure of the exact details, though)