Resolving the Error and Accessing the Marketplace
In order to download apps and games to your Windows Phone you need to ignore the Marketplace Hub on your phone, and instead access the library via your computer. The following steps can only be performed on Windows computers with the Zune client installed -- if you don’t have it already, you can download from www.zune.net.
These steps also require you to access the Windows Registry -- this can be potentially dangerous if misused, so if you’re concerned about making any mistakes find a more confident associate to carry out this process.
After installing the Zune client, go to Start and type regedit into the search box and hit Enter. Find your way to HKEY_CURRENT_USER\Software\Microsoft\Zune\Features, where you will see that the entries for Apps, Marketplace, and SignInAvailable will all feature a long string similar to this:
What you will need to do is add the two-letter shortcode for your country to the end of each of the three entries; for instance, if you live in South Africa, you would add SA:
Simply double-click the Apps, Marketplace, and SignInAvailable entries in turn and then update the string, and click OK to confirm each one.
Once the change is made, exit the Registry Editor and connect your Windows Phone to your computer. Zune should launch, and the “Features Have Changed" message will be displayed. In Zune, you should see the Marketplace link in the menu, and you will now be able to install apps!