Dear Ines,
I have only worked with GenOpt + Trnsys 16... I heard that the steps are the same, but I'm not sure...
Where did you get this error message from? I don't think I ever saw such an error message...
What I know is that you see the errors in a file called "Genopt.log"... Actually it might have a different name, but the extension is ".log".
If you open this file you can see the error...
Can you please check for that file and let me know if you found it and if the error is more clear?
Best of luck,
Amr