When trying to checkout using the latest version of world pay, I get

Catchable fatal error: Object of class queryFactoryResult could not be converted to string in

A bit odd!

PHP Version: 5.2.0 (Zend: 2.2.0)
Database: MySQL 4.1.21-standard-log
HTTP Server: Apache/1.3.37 (Unix) mod_fastcgi/2.4.2 mod_gzip/1.3.26.1a mod_auth_passthrough/1.8 mod_log_bytes/1.2 mod_bwlimited/1.4 FrontPage/5.0.2.2635.SR1.2 mod_ssl/2.8.28 OpenSSL/0.9.7a PHP-CGI/0.1b

Zen Cart 1.3.7
Database Patch Level: 1.3.7