Drawing not publishing

Last week we upgraded to Windchill 12 and Creo 9.0 with CreoView Adapter 9.1.

When we submit a job to the CreoView, the model files (parts and assemblies) publish fine and benerate thumbnails that dhow in Windchill. The drawings do not publish a viewable or a thumbnail. When I open a drawing in CreoView, it only opens a blank page, no drawing. Models open fine and can be viewed and manipulated.