Please tell us what PLC the file is supposed to be for. You originally posted the file in a thread related to a Series Six PLC. For that, you need Logicmaster Six (which I have) to open it. If the original file extension is .lad, it could also be for a Series One, Series Five, or even a Series Three.
If it is a PMC program for a Fanuc CNC controller then you need Fanuc ladder which I don't have. Good catch there, Bill4807. I didn't make the connection between the PMC1 name and the CNC controllers. I put the blinders on when I saw the .lad reference.