File upload issue

Hi all, In my php.ini file, file_uploads value is set to OFF. Hence stopping HTTP_UPLOAD functionlaity. But in my script i am turning it On using ini_set("file_uploads","1") but still it doesn't upload the file. I don have access to modify the php.ini file hence trying to play with script only. Though manual says u can't set the value of file_uploads in the script, but its getting set (looked in phpinfo()). Why this is happening ... and if it is getting set why HTTP_UPLOAD doesn't work. Thanks in advance Binay