Hi
Darryl NG
I had the same problem, got it solved by changing the MABS version that generates the mobile app. I was using version 7.0 and changed it to 6.3, which solved the issue.
I solved going into the Service Center -> Applications -> Your app -> Tab Distribute. Click in Configure (for the platform that you pretend, iOS or Android), and then you can change your MABS version.
After the change tries to generate again.
Check the screenshots.


Regards,
Gonçalo Almeida