Instead of checking for the MAC ID, I would suggest checking to make sure that the file is open. Also, your code is going to need to make sure that the correct window is open before it starts adding records. Otherwise it will just be adding records to whatever database happens to randomly be the top window -- which is almost certainly a BAD thing.
As for this running automatically when you open it on the server -- where is the code that defines the variable? If it is in the .Initialize procedure, that doesn't get run on the server. Instead, you need to set up a procedure named .InitializeServer.
I don't have time to check this right now, but it is possible that the server itself uses the ExecuteEveryMinute variable. So if it does, you will be stopping the server from doing periodic tasks. I think it might be using this for periodic backups, so you are probably ok if you haven't enabled those. But I am not sure about that. This is part of why Panorama X has a new system for running code periodically, which allows different tasks to run periodic code independently without interfering with each other. But of course that won't help you at the moment.
I had a similar need and solved it a completely different way. Instead of running a timer locally, I set up an external monitoring service that "pings" the server periodically with a URL of my choosing. I set up a URL that runs a Panorama procedure with my periodic task. If once every 5 minutes is enough, you can find free services for this. If you really need once a minute you'll probably have to pay a few dollars a month. As a bonus, these services can also notify you if there is no response, so you're also getting downtime alerts if there is any problem with the server, the network, or Panorama. The whole system has been in use for over a year and works great. I actually set up 2 external monitoring services for redundancy.