The GXV160 engines are just about all made in China these days, and have been for some time. It doesn't seem to be a problem.

Here is an exploded view of the wheel parts, with part numbers, from the Honda parts list:
http://www.planopower.com/store/honda/honda_rear_wheel_hrc216s.php

As with many Honda designs, it is rather complex compared with many other mowers, but probably works better than most as well. I think you can clear up your problem just by identifying the parts from the exploded view, and seeing whether you have them all, as well as how to put them together.

Being a self-propelled Honda, that is a very expensive lawnmower, which looks rather new, but would probably sell for peanuts on ebay in an incomplete non-functional state. I'm not up with current models but that one may be a "parallel import" of an American model not imported through Honda Australia and not warranted by them. It is probably less than an hour's work to put it together and make it worth over $1,000, provided you have the grass catcher for it.