That phone doesn't have a touch-screen, does it?
The windows phones are confusing... Touch screen that are running Winmo 5 and earlier and those running Winmo 6 and later and Non-touch screen...
But it sounds like you downloaded the wrong version, maybe?
Did you use the mobile site to download the app? Or did you download it to your computer?
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This link will provide you with the general information about the Windows non-touch screen Mobile devices. Note that the T-Mobile Dash Mobile device is only supported by the SlingPlayer Mobile when on Wi-Fi connections.
Devices and requirements
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