Error exporting mp4 in dolby renderer with ADM file created in Nuendo 12

Hi.
I’m having an issue with Nuendo 12 that I didn’t have with Nuendo 11.
When I use the ADM file created in Nuendo 12, the file works fine in Dolby Renderer v3.7.2 but when I try to export to mp4 it keeps showing me a “Runtime error”. When I use the ADM files created with Nuendo 11, there is no problem. Am I the only one having this issue? I can’t figure it out… I’m doing exactly the same procedures that I used to do in Nuendo 11.
Can anyone help?