This has been reported by a few people, sorry I've taken so long to come up with a fix.
I think I can reproduce this, so I may be onto a solution. It may be the result of a faulty installation. This is likely if you are a Real NZ subscriber, as the initial shipment of CDs was not picking up the correct FS location if it was changed from the default location.
If this applies to you, and you are getting crashes, then you should try this:
Locate a file called FL994460.bgl. This is located in the Flight Simulator 9\Scenery\Ocen\scenery folder.
If you cannot find it, then your installation worked ok. If you can find it:
Rename it to FL994460.GVF. (just change the extension to .GVF)
Let me know if this helps.
The problem may be caused by duplicated flattens for the lower half of the North Island. Renaming this file effectively disables it, leaving only the one set of flattens for this area.
This would also explain why deactivating -- or even deleting -- Real NZ Wellington doesn't fix the problem, as the offending file will still be duplicated in the Scenery\Ocen\scenery folder.
... but with both 9 and X runnin get a lotta conflict , but
seems to work .