Magento Expert needed to fix Invoice Problem

Hi all,

I am almost ready to go live with a new Magento store. I have come across a problem when printing invoices from the admin area an error is thrown:

Invalid method Mage_Core_Block_Template::toPdf(Array

I am unable to fix this and have looked through lots of forums.

I need this fixing to enable us to go live. I would also like to potentially work with the freelancer on some payment gateway modifications - but for now this is the pressing issue

Please let me know if you have come up against this error before or if you think you would be able to fix this

Regards