Can't export canvasses into other formats
 

I created a canvas with multiple layers. When I try to export the canvas showing just a single layer, I get an arcane error that reads:

The document “CGSH DCC Dependencies Phase 1.graffle” could not be exported as “CGSH DCC Dependencies Phase 1-L1”. Failure when trying to produce data of type GIF Format - check the console for messages

What does this mean in layman's terms?

One thing it doesn't mean is that OmniGraffle can't do that. I just made a document with a couple of different layers on a canvas, turned off printing on most of them, and exported the remaining one as a GIF file without incident.

Open up the Console application (it lives in the Utilities folder in your Applications folder). Click on All Messages on the left, then type OmniGraffle into the search box at the upper right. Mail whatever is left to [email]omnigraffle@omnigroup.com[/email] and see what they have to say.