Ok, the module is: http://addons.oscommerce.com/info/1589 Step-By-Step Manual Order Entry
It doesn't make sense, that only one file was modified, and then when the error occured the original file (back up file) was put straight back over the top and the error stayed. I don't think its a module thing, because all the code is the same as our other sites......
Would it help if i pasted the create_order.php file & the sessions file?
Thanks
Jode