1GB file upload using php

[lalptaug]

I am trying to upload a file of 1GB size using php script and it works perfectly if file size is less than 20MB, but when I increase the file size than after pressing upload button on website, it uploads the file (I guess as it takes few minutes) and after that, instead to execute upload.php, my firefox asks me to download upload.php, so I guess, file is being uploaded but my php script fails to execute.Also after searching in google I found following settings for php.ini which I made and my php_info() function shows me that settings have been changed../*php.ini start*/memory_limit = 512Mpost_max_size = 15000Mfile_uploads = Onupload_max_filesize = 15000Mmax_input_time = 20000max_execution_time = 20000session.gc_maxlifetime = 20000/*php.ini end*/Please help me out to resolve this problem.....Thanks..