inconsistent behaviour transferring a virtual server to a cloned VM


to better understand how to move websites around between servers i created a debian wheezy vm(1), installed virtualmin and then cloned the vm(1) to create vm(2). each has its own static IP address.

i created a drupal site on vm1 and then transferred it, along with the database to vm2 (in a couple of clicks - how cool is that!). all looks good apart from one small glitch i dont understand and i would appreciate some help…

on vm1the Virtualmin=>Server Configuration=>website options=>PHP script execution mode is (automatically, i guess) set to FCGId and the website wont load if I set the option to “Apache mod_php”.

on vm2 the reverse is true. PHP script execution mode must be set to “Apache mod_php” and doesn’t work if I set to FCGId.

I understand the difference between the two but i dont understand how the two systems to differ to cause this behaviour. looks like a permissions issue but i cant work it out myself. any assistance or insight will be very much appreciated.