That sounds like gimbal lock. It's a problem prevalent in many 3D programs, and is not exclusive to Poser. No need to go through Rhino and UVMapper again. Stand the table in an upright position, export from Poser in .obj format, and import the new mesh. That should "correct" the axes. Or you could use Poser's grouping tool to spawn a new prop from the table. That should set things right, also.