Poser generally issues an error message if there is anything in the CR2 that it can't find, so it seems to think it found the necessary items, but is refusing to show them to you. The scale could be extremely large or tiny....
Or the Save As Character decided to only save a small part of the car AS the whole unit.
if it's the latter, I'm sorry to say, all you can do is start over.
It helps to save your Poser file often with different names at every step of the creation process.
Car-Imported, Car-sorted, Car Hierarchy, etc. This will prevent the loss of all work in the event of an error or (in my case) a change of mind.

;>

Andy!