HELLLPPPPPPP.. Checkout error.

Hi All,

pleaseeeee someone help me, i pretty much have everything working how i want it but when using the standard opencart checkout, i get a massive error when i've selected either guest checkout or register account. when i press the continue button a massive error comes up. i have no idea what it is or how to fix it. If i press enter on the keyboard the message goes away and then comes up again, i press enter again and it goes away for good then allows me to finish the checkout process. but this happens everytime you try and checkout.

Are you using default theme or customised ?

'route=checkout/checkout/custom_field&customer_group_id=1' causes the error.

Check catalog/controller/checkout/checkout.php

Is it the version belonging to OC2.0 and has it it function 'public function customfield() {' at line 123 ?