Debug code that writes files to Linux file system. Used for Asterisk PBX server. -- 2

Debug this code, alter it and get it working!. It's not my code. I am running an Asterisk server and want offline text messaging. This code checks to see if an extension is online, if not, it writes a text message file to a folder ready for delivery when an extension comes back online. It should be straight forward but I suspect that a function or two is failing, possibly something to do with the version of linux I am using. I am running it on Ubuntu 14.04. All credit, details for the code can be found here [login to view URL]