The remote host is missing an update to atftp announced via advisory DSA 314-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20314-1

Rick Patel discovered that atftpd is vulnerable to a buffer overflow when a long filename is sent to the server. An attacker could exploit this bug remotely to execute arbitrary code on the server. For the stable distribution (woody), this problem has been fixed in version 0.6.1.1.0woody1. The old stable distribution (potato) does not contain an atftp package. For the unstable distribution (sid) this problem will be fixed soon. We recommend that you update your atftp package.