Oh ok, I now know what was the difference between your first correction and the second.
Now I don't get the blank page on confirm.php.
Instead, I get this error message saying;
" Unknown column '2ecba4fbadb9fc4ac979b238efbc1ef9' in 'where clause' "
What's between single quotes ('2ecba4f~) varies by ordered products.
I must have done something wrong on setting value in the column?
Or it this a problem with dataset binding on a product page?