Setting up MAMP to work with LESS

Hi

I am new to developing with .Less and wanted to experiment with T3 on my local computer. I have set up and installed T3 on MAMP on OSX and all is working fine except when I switch on "Enable Development Mode". This caused the template to load with a blank page on the front-end.

I am assuming that this is to do with the setup of PHP under MAMP. What do I need to add to the installation to that the browser runs with .LESS

Any assistance would be most appreciated.