We retired the App store on June 30th 201, if you are accessing applications via the Leap Motion app store then this will be why they are not working correctly.
These apps are now available via the Leap Motion Gallery which can be found here with some FAQs available on our help center here.
Remember to check the SDK version that is required to run the app. A lot of the older Desktop apps were built for our V2 SDK whilst the newer VR apps were built for use with V4. We know that it is confusing having App Home installed along with the SDK when it has been retired and this will be removed in the next release.