Cannot connect to Serviio server, it does not seem to be run

It appears that the Derby Driver has disappeared - probably my fault. I've tried installing 1.8 and get the same error. I've downloaded the zip and would like to know which jar and where to install.

Placed Derby.jar into Java Extensions folder. Deleted Serviio folder in Application Support. Deleted Serviio Console. Restarted computer. Installed 1.8. Restarted computed. Console started. Reloaded license file, reconfigured server settings.

I am using Serviio 1.8 on a Mac Pro 3,1 early 2008 running OSX El Capitan 10.11.6 and I have started getting this error. It been rather annoying as it happened not long after I paid to upgrade to a Pro account. Serviio has been running so beautifully up until this error too!

I have tried deleting Serviio and the library files and then re-installing to no avail. Any suggestions? Might this be related to a recent OSX Security update?

I would like to resolve this because I will be setting up another Mac as the home media and printer server.