Error code 1 occuring when connecting to Infobip's SMPP server (to send sms) using PHP

I 开发者_开发问答am trying to connect to Infobip's SMPP server with the code below but am getting error code 1 invalid message format. Please could someone tell me what the problem is. Please could someone also tell me if there is a better code that I can use. The code am using is on this link