I had the same problem with importing text from Illustrator. I could not get it to Create Shapes from Vector Layer in After Effects. I think I may have found a solution.
In Illustrator, select the text and try Object-Expand. Import the Ai file into After Effects. If you have more than one layer, you will have to repeat for each layer. Then bring it into the comp and try to Create Shapes from Vector Layer. You should then be able to convert the newly created layer to a 3D layer and extrude it (under Geometry Options). Make sure the Renderer is set to Ray-traced 3D.
Glad I found this thread because I had problems with all of the other issues, too.