Help going from UI6 to UI5

I don’t know if this is the right forum …but here goes. I have a Vera 3 on UI6 (1.6.641) and have developed issues with random reboots and full LUUP crashes where Vera 3 doesn’t work unless recycling power. I have gone around and around with tech support and all they have me do is remove plugins to see if that’s the problem. Anyway, I tried to go backwards to UI5 but something is obviously not working. I go to Setup>Firmware…type in this URL http://download.mios.com/rt3662_betafirmware/rt3662_Luup_ui5-1.5.622-en-mios.squashfs for Vera custom firmware and click download. I then get a 15 min timer and I click to install with current settings. I wait and nothing happens except after about a minute I get a message that says “Luup : Failed to download all plugins. Will retry in 10 minutes.” This message won’t go away now and no downgrade to UI5 occurs. Any idea of what is going on? how do I remove this Luup message? is there another method I can use to go to UI5 with my current settings?