This is just to confirm that the above solution worked of me.
Softaclulous was only working for some users and not others.
On the users that it wasn't working on it would only produce a white page, or download the index.live.php page.
I had concluded that it was a php error in that some modules/plugins may not be present on some accounts but were on others, however I didn't fancy a huge trial and error test run.
I followed the above instructions to change users to use cpanels version of php and everything works fine.