Well in the Filedatabase, make a php.ini file.
In the php.ini file make the highest fileupload to 20 MB or higher if needed, and upload it to the maindirectory where the script is working, so I would proably say where the admin.php page is or the index.php.
If you want you can download my default 20 MB php.ini file. I didn't change anything other than the maximum upload size.
By placing this in the directory where the script is running, will overrun the server's default php stuff.
php.ini.zip
zip file 13 KB,
ini file 40 KB