If a run-time error ‘713’ message appears when attempting to open NetCon, then this is a good sign that TRANSYT 12 has not been properly installed onto your PC.  Please note that you cannot simply copy and paste the contents of the main TRANSYT 12 folder from one PC to another, and then register it.  You must always use the official installation package to install TRANSYT 12 onto a new PC, to ensure that it will function correctly.