Well the error indicate that the host was not found. You may have lost the connectivity on your device, or have a host down, etc.
socket.smtp is part of the AAF framework (which is why you do not have it in your sources). The file is embedded in the ALEOS firmware under /usr/readyagent/lua/. You can also get a copy there: w3.impa.br/~diego/software/luaso … l#download, we are using 2.02 version.