File uploads do not work
If no files are uploading at all (large or small):
check the permissions of the folder /includes/plugin_file/uploads/ - try changing these to 777 - your hosting provider can assist with this.
If large files are not uploading, but small files are uploading fine, then:
Try going to Settings > Advanced and change 'file_upload_old' from 0 to 1 and then try the upload again. If that does not work then open FTP and look for the file .htaccess in the main UCM folder and add these two lines of code to the very end:
php_value upload_max_filesize 100M
php_value post_max_size 100M
If that still doesn't work please email the hosting provider and ask them to increase the file upload limit for your hosting account.