ReadyNAS 102.... Apps not installing

SOLUTION
This is for anyone encountering the same issue as I had.

Netgear support directed me to this app page http://apps.readynas.com/pages/?page_id=9
Where I downloaded an older version of Plex media server. [plexmediaserver-ros6-binaries_0.9.7.28.0-d1f35c1-netgear2_armel.deb]

If you want the direct link here it is http://apt.readynas.com/packages/readynasos/dists/apps/pool/p/plexmediaserver-ros6-binaries/plexmediaserver-ros6-binaries_0.9.7.28.0-d1f35c1-netgear2_armel.deb

I uploaded this app via the frontend and received the same successful message as before except this time the app showed under the installed apps menu and I was able to toggle the service on and get it working.

I am yet to find out why the downloading from the available apps menu is failing and also I downloaded the readynas surveillance app from the app page provided by Netgear support and although the install was announced as failed and written in the logs as failed I can see the app installed and can toggle the service on.
It's clear there are some bugs in the OS at least on my device but the end goal was installing Plex Media Server and it's on there now. Don't even want to think about upgrading plex versions anytime soon.

Thanks to StephenB and mdgm for their advice. I hope this helps someone else out there.