I was not aware of some devices not being supported when I ordered my P3P. In preparation prior to receiving it I installed the DJI Go app on my iPhone 4s. Alas, after connecting the phone to the RC and powering up the P3P I got the same problem you did... camera button was grayed out and the app would not run. After some digging I realized the 4s was not supported. So I go to my local Walmart and purchase a Nextbook for $80 that I figured I would dedicate to the Phantom. However, the DJI Go would not even install on that tablet... just said device not supported. Better stick to the list of supported devices, albeit the list can be somewhat deceiving as the Nvidia shield is not on the list but apparently works very well.
I'm afraid that your Insignia my no longer be supported after the latest FW upgrade.