The file /var/www/vhosts/site.com/httpdocs/mysql.php was encoded by the ionCube Encoder for PHP 4 and cannot run under PHP 5.5.
Please ask the provider of the script to provide a version encoded with the ionCube Encoder for either PHP 5.3 or PHP 5.4 or PHP 5.5. in Unknown on line 0.
Is there a way or a trick to overcome this?
You could try an ionCube decoder, but the whole idea behind encoding it is so you cannot get at the sources. It's probably not allowed by your provider to hack their encoded PHP code. So, no, there's no trick other than contacting your provider.