I have 3 sites hosted through my dreamhost account. I uploaded the dh-phpini.php file on one site and increased the max_file_upload size to 20MB in the new php.ini file. However, when I upload a larger file (still under 20MB), the site stops and ALL the sites hosted show a 500 Internal Server Error.

Any ideas why this is happening and how I can fix it?

Please treat my like a novice because I am.