Custom Payment Gateway returning Blank Page

I'm trying to create a custom payment module using the example payment plugin found at www.hikashop.com/index.php/support/docum...r-documentation.html

They payment gateway works pretty much the same so I've hardly touched the code and after entering the credit card details on the payment gateway return, im returned to a blank webpage:
mydomain.com/index.php?option=com_hikash...ample&tmpl=component

I specified that url as the return url for successful and unsuccessful messages from the gateway. Is it correct or is my blank page a result of something else?

The source of the blank html page reveals a header with all the js and css loaded, but the body is empty.

Hi,
Note that checking that thread will probably help you.