Proplem uploading

i having proplem uploading, i can upload file that is 300 kb but not 900 kb.

Still the
upload_max_filesize = 4M

and i use

ini_set( 'upload_max_filesize', '10M' );

What is wrong with my script?

I commented the upload part out so you guys would not flood the server.

Hope you can help

Jokull