Sometimes, when you open up Vinylmaster, you may be unable to send jobs to the cutter, or save your work, as in the image below.
When this happens, usually it's because the software is not activated. Vinylmaster can be deactivated on accident, and sometimes happens after a Windows update, or other software changes. To fix this, you can just activate the product by choosing Help > Activate Product...
And then hitting activate.
If your software PSN is already registered in the program, it should just activate the software, as shown below. Otherwise, you may need to enter your PSN in order to activate the software. If you do not have your PSN, you can try to find out How to locate your PSN for Vinylmaster.