Permissions settings in My Script

Hi i'm creating a php script that copys a directory in to another using a dir_copy funcion that i created, now i want to create another function that deletes this DIRECTORY if it exists.
When i use the unlink() function to delete the subfolder in my directory i get Warning: unlink() failed (Permission denied) i tried changing the permission settings chmod($filename,0777) before i delete the files but no difference can anyone help?

Where is the site being hosted? If its with a typical webhost on the internet they may automatically reset the permissions to something they deem acceptable to avoid people setting mode 777 on just anything.

-KM-