If you have changed the marketplace region as I described in the previous post and now you try updating applications that were installed in the old region, you are probably going to get the next error:
“We’re having a problem with this app or game because it no longer appears in your purchase history. This can happen if you’ve recently switched the gamertag associated with your Windows Live ID. We’re sorry, but you’ll need to buy this app or game again to continue using it.”
And now this application is stuck on your phone, you won’t be able neither to update nor to delete it.
The only work-around I’ve found so far is reinstalling the application through the web marketplace. So go to windowsphone.com/marketplace, search for your app and hit ‘Reinstall this app’ button.