Hi Colin,
I apologize that I didn't mentioned the solution in the previous post somehow I just forgot it.
What I did to solve the problem was a change in my php configuration.
With php 5.5 I got many error's and could solved it with a work around in the TemplateSet.class.php and changed this area
"public function show($tpl_name, $checkskin=true, $force_base=false)
{
return $this->ShowTemplate($tpl_name, $checkskin, $force_base);
}
to true, but I have to set it back each time I want to make a change in the VA, so that was not an option.
The second and final solution I did was simply upgrading my php configuration from 5.5 to 5.6 (C-panel).
This solved my problem for good.