The remote host is missing an update to samba announced via advisory DSA 2450-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202450-1

It was discovered that Samba, the SMB/CIFS file, print, and login server, contained a flaw in the remote procedure call (RPC) code which allowed remote code execution as the super user from an unauthenticated connection. For the stable distribution (squeeze), this problem has been fixed in version 2:3.5.6~dfsg-3squeeze7. For the testing distribution (wheezy), this problem will be fixed soon. For the unstable distribution (sid), this problem has been fixed in version 2:3.6.4-1. We recommend that you upgrade your samba packages.