Fatal eror when using Cheque payment method in version 1.4.0.6

[rudders18]

Hi
Has anyone come across a problem after upgrading 1.3.1.1. to 1.4.0.6 where you get a "Fatal Error" message when clicking on the "I confirm my order" button in the cheque payment module. It seems to only happen with customers that existed pre the upgrade, I raised it as a bug as I can reproduce it every time but the development team cannot reproduce it so they have closed it but it now makes Prestashop unuseable for me and I do not want to change to something else.

I have removed all non essential modules and I am testing with the default theme.

Any suggestions most welcome.

Thanks