Hi, first of all, can you tell us a bit more about your DR setup? The more details, the better.
1) Are any other parts of your scene also becoming transparent, or render incorrectly? (e.g. lighting and textures getting brighter or darker)
2) Are your proxy files stored on the master machine only, or maybe on a network drive accessible for all of the PCs taking part in DR?
3) Which version of 3ds Max and Backburner are you using on all of the PCs taking part in DR?
We also have this general DR guide, which you may want to check out for basic information:
https://coronarenderer.freshdesk.com/support/solutions/articles/5000501666I'll be waiting for your feedback, hopefully we will solve this soon!