I'm having a problem with a site i'm working on. I'm getting a blank page when i click the button to go to the 2nd part of the checkout procedure.

I've downloaded and installed the error logging tool and it came back with this error message:

[09-Feb-2009 13:16:53] PHP Warning: Cannot modify header information - headers already sent by (output started at /home/u30chri/public_html/sienna/includes/languages/english/modules/shipping/cherry_zen/flat.php:53) in /home/u30chri/public_html/sienna/includes/functions/functions_general.php on line 44
Now I have been discussing this with a few people on the Zen forum as initially I thought it was probably the functions_general.php page that was at fault, see the following thread http://www.zen-cart.com/forum/showthread.php?t=119717... But following some further advice i've got it appears that it may be a page in the cherry_zen template folder, flat.php

I've notice that flat.php isn't part of the installation package for cherry_zen so the file must be dynamically created by zen cart or cherry zen itself.

Can someone please tell me how/why this page is created, and whether from wat you can see from my screen grab what's wrong with the coding. At present line 53 on the flat.php page is blank!!!