The remote host is vulnerable to multiple attack vectors.
The remote host is running phpBB, a web-based forum application written in PHP. There is a flaw in this version of phpBB that will allow a remote attacker to disclose paths. This sort of information may be useful for further attacks. There is another flaw within the usercp_avatar.php script that would allow a remote user to pass arbitrary files to the unlink() function. The unlink() function deletes files. A successful attack would delete arbitrary files on the web server.
Upgrade to version 2.0.12 or higher.