I tried 4 other panels and had the same issue. I am not happy with this purchase at all. And this all goes back to my general dissatisfaction with most electronics related devices - not enough quality control. When I complained to TEK2000 and Satellites-Gallore about the carriers rough handling of the product, I got no response. Too bad I wasn't present when the antenna was delivered - I would've refused delivery. I guess I can try to make some minor corrections to see if I can get it to go together.
Well, I would be tempted to buy a LOT of C-Clamps for use to do this. Harbor Freight sells some good ones for this purpose, but C-Clamps are always useful.
Do all this assembly on a large hard flat surface, such as a concrete driveway if possible. Get a pail that's high enough to put in the center, as you do this with the panels face-down. Perhaps shim it a bit with some old books or something, if you need a bit more height. Get all the panels lined up that have matching bolt holes that don't need re-drilling, and bolt them together, but NOT torqued/cranked down.
Try to do a complete 1/2 of the parabola this way with all matching holes. Hopefully there's enough panels that are drilled properly. If not, do as many as you can with bolts. Once you are sure you have all of those, start bolting the badly-drilled ones together with any matching holes, until all that's left are the holes that don't match.
On those, try using the C-Clamps to clamp the edges together (maybe using thin woods shims so it doesn't deform the metal), and get them all fitting to where it looks good, the rim seems level and all seems as if it should be good. You might even be able to string it at that point. THEN re-drill the holes and use the last bolts. By the way, I wouldn't use the Chinese bolts that come with it. Every time I've tried that, that last little crank causes them to break.
It might take longer to get everything to where you think it looks good by doing it this way, but it is, what it is, and at least this way, you can make any changes before drilling holes and being 100% committed to whatever happens.