Not able to Export 4k 50 FPS - error if trying aramezan's post solution with hardcoding the .xml file

Hello, 

I want to be able to export 4k 50 FPS video from Virb edit as currently I only get the 25 FPS option.

I've tried the method presented in aramezan's post but I get an error (see link image)

Can someone help me with this error ? 

Is there any other solution to have the 50 fps option ? thank you

https://imageupload.io/i/Arm89ssyKg