unable to load media url
Using Jamroom
My first thought is that it's something to do with your new custom server setup. That has broken other things, so that is probably the cause of your issues here as well.
Could be that that is breaking your keys now, or it could be that you broke something to do with your keys when you reconverted. I'm not sure, but I expect that if you tried it on a working server that all would work fine.
Did you already fix the php misconfiguration on your server? Or are you still trying to troubleshoot that at the same time as troubleshooting this?