insert PHP script into page

I have use a couple of “insert PHP” plugin to try to get a script working on one of my pages

http://oandh.com.au/cars-2/ is how it should look (however this is in an iFrame and this is stopping many of page features – like image enlagement etc)

so it needs to be embeded

http://oandh.com.au/cars-3/ has the php code using the instructions from the plug-in developer
the code is

[insert_php]
ob_start();
[/insert_php]
{CRL_LISTINGS}
[insert_php] include '/home/oandhcom/public_html/cars/app/views/pjLayouts/pjActionListings.php'; [/insert_php]

ie changing the normal PHP tags to the ones they suggest

but the page just loads blank – could this be theme related?