ini_set Problem

Hello all, I want to upload around 10 mb file size.... and i am using windows server i write the following code ini_set("memory_limit","25M"); ini_set("post_max_size","50M"); ini_set("upload_max_filesize","20M"); set_time_limit(0); and i also specifiy MAX_FILE_SIZE hidden variable in Form .... but it give me UPLOAD_ERR_INI_SIZE error means File size exceeded php.ini value... I do not have writes to change the php.ini... So i must have to set it by ini_set function........but its not working...... Any idea whats going wrong and how can i solve this problem..... regards