Open that file up and add:
name=XXVII Grand Prix de Belgique
trackShortName=Spa Circuit National de Francorchamps
Making sure that the event is numbered appropriately and at the top you have numEvents=xx equal to the number of events listed in the season file.
Also, to avoid this problem in the future, make sure that you have the latest SGEM file. Go into GEM > Seasons window and click on the SGEM button at the bottom to update it.
Edited by Bob Simpson, Feb 10 2017 - 11:28 AM.