Hi Guys,
First of all, the 1.1b2 plugin is now posted, Mac and Win:
http://www.xsquawkbox.net/tools/ac3d/
If you try this and still have a problem importing an object, please email the object to me! I have not had trouble importing any valid OBJ file.
You MUST remove the obj_import.p plugin from the default plugins that ship with OBJ -otherwise AC3D will try to import your x-plane OBJ as an alias wavefront object.
*Cheers*
Ben