The software serial port operates differently than the hardware serial port and might be causing timing issues.
Not likely, since OP isn't even creating an instance of the class.
And I am unclear as what you mean about the enter key. A good section of the html code is copy pasted.
// ADD: Set Extron_Input= ?___ // What ever is after the 01. It will set the value to. So if ?i12. Then it is looking for Input 12
There is no excuse for putting a comment this long on one line. Having to scroll back and forth and up and down to get to the scroll bars on the code window makes me want to just hit the back button and ignore you.