Thank you for your response.
I have checked the testing server model for the site and it is definitely set to ASP VBScript and not PHP.
I have once again uninstalled all my extensions, then deleted the configuration folder, then re-downloaded security assist, then reinstalled my extensions again (quite time consuming!).
I am still getting the same error and the pages are still being created using php.
Are there any logs or anything that i can provide you with to aid in resolving this issue?