chmod directory threw php ?

[chad777]

I am working on a hack for vbulletin and another program integration. The only problem I am having is

I run this command in one of the scripts:

PHP Code:

chmod ("$p_directory/dir i am making", 0755); 


but I get and error like this when testing the script

Warning: chmod failed: Operation not permitted on line xx

is there another command I can use to chmod ?

or do I have to do something to my server to allow php to chmod ?

Any ideas will help thanks