Thanks for sending a sample file. In this case FAB 3000 doesn't detect 0-width lines (typically border outlines in Gerber consist of traces with width).
Please perform either of the following:
Here's a quick tutorial showing how to perform that task.
Note: We will search into why 0-width objects are not used in Border detection, and if possible create an update that accepts 0-width objects.
Lastly, here's the most bullet-proof way to create a border:
Here's the movie tutorial showing those steps (with a bonus PCB realistic preview):
Let me know if that helps.
I downloaded Version 7.7.7 from your site for trial and studied your
tutorials and documents.
Sadly i cannot create a border using the automatic or the manual mode
from a lot of data.
Eg the simple file attached - how can i create a border from it?