This means that the “log4j…” lines in your servoy.properties files are not as they should be.
You can remove them alltogether and new default ones will be generated when starting Servoy.
You could then compare the default ones with the ones you currently have - maybe you can notice what the problem was.
It could be that this comes from the log plugin. Maybe the log (server) tries to create a logger before Servoy inits its logger. It should not matter anyway. Could you try and see if the “error” is gone without log plugin?