Sorry to hear of your problem. I'm surprised your dealer didn't know the difference and also ordered the balloon wheels instead of the complete Trax cart. When I looked into this the separate wheels cost almost as much!
The Trax cart has a longer and stronger axle (solid 1/2" bar as opposed to 1/2"tube) necessary for the wider balloon wheels.
You can fit different wheels to the Trax cart. The Hobie heavy duty pnuematic wheels fit.
I posted a an extensive how-to here:viewtopic.php?t=8956
but it has been lost in the forum upgrade.
(Why is that Matt??)
The standard cart wheels can also be made to fit using simple spacers.
I'd be talking to my dealer about a cart swap!
Using the search function will bring up more useful info such as :viewtopic.php?f=11&t=11408&hilit=trax