This relates to when you are seeing a run-time error on basic operation of your FastCAM 7 or FastNEST 7.
Usually it presents with an error like the above, or it could be that your FastPATH settings are not staying put after updating them, and you need to update them everytime you run FastCAM / NEST.
The solution to this is to clear your temporary files. However, that may not be enough. So first we recommend checking your UAC settings, as per this guide:
Once that is done, then you can clear your temporary files, as per this guide:
This should solve the problem for you!