Docker CLI Addon for ReadyNAS 6.9.3 - Installation Failure

Hi guys, completely new here. I've just purchased a Netgear ReadyNAS 214 and just setting it up now.  I'd like to install Docker on it and from what I've learned so far, Mhynlo has put in a bit of work on getting this to work.  I've tried downloading the latest stable and pre-release versions from here:

 

https://github.com/Mhynlo/readynas-docker-cli

 

Unfortunately, I'm having a bit of trouble getting it to install.  I keep getting an "Cannot install application docker-cli-rnapp" error message.  Help?

 

My goal is to have my ReadyNAS spin up icloud_photos_downloader (https://github.com/ndbroadbent/icloud_photos_downloader) pull files from iCloud on a scheduled basis to backup to storage on the NAS.  It's a different approach than ReadyCLOUD and it gives me more control over how files are backed up:

• An app also doesn't have to be installed (and managed by the end user)
• Backups are initiated from server-side and not client-side on the device
• Backups are not managed on the device, which can be confusing for a non-technical end user
• Delete older content from iCloud if it is already backed up to NAS; This maximizes the use of cloud storage space

Any help greatly appreciated!