After the upgrade to 3.7.1 I get this error in the checkout process:

Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in /home/honestin/public_html/includes/functions.php on line 0

Warning: Cannot modify header information - headers already sent by (output started at /home/honestin/public_html/includes/functions.php:0) in /home/honestin/public_html/cart.php on line 0

I know usually this means some blank space, I upload the few files I modify, check all, and nothing. Also I'm waiting the reply to my ticket, but perhaps someone have the same problem?

wow! many thanks, finally was a misterious space in the configuration.php file, Matt repair it.

Great :) It's good the support of WHMCS is this good.