I'm sorry but for the first time I'm seriously disappointed in a Roku product. The point anywhere remote that comes with the 3800 stick is a complete fail! I'm on my second remote and it constantly stops working! It's pretty much useless! I've been through all the troubleshooting steps multiple times and it continues to hang up or stop working all together. If I didn't have the remote app on my phone I wouldn't be able to use the device at all! At this point I'm ready to return the device yet again and go with a standard IR remote which doesn't have the problems that this one does. It will certainly be A LOT less frustrating!
Did you try the HDMI extension cable? It always seemed to me that putting a device behind a TV that almost certainly generates RF interference is a bad idea. Just one reason I've always avoided the sticks.