Swarm agent failed to determine engine directory!

I started a new project and since i updated from 4.7 to 4.8, later to 4.9 but the problems are still appear, I have enourmous problems with rendering and light building.
In older project the light was builiding always before, but since i updated i can´t build the light. I thought its a local problem and updated all my drivers to the newest version. Also i installed Unreal Engine 4 again and tried.
So i stopped by now with light building and was waiting for a new update.
To see what is really the problem, i created a new project with a little landscape, a waterplane and 5 palms.
I started again to build the light with a lightmass importance volum, but by now it doesn´t works.
I searched through a lot of questions ut the most answers are not really helping.
I started to setted the settings in a new way and i had a little success that the coordinator and the agent ae woking togther, i setted all lights to dynamic lights and i have by now the Lightmaps under 256.
Also i restarted and did all what i could find to get it working, but the light still stucks by 98% for hours, what isn´t normal, when all the other process was finished in seconds.

I need a working soultion and not an example of ways what can help, also nobody who say, that its because of the RAM, because never my RAM was more than 70% and how i said it was working before with the same pc and a more larger size of world.

Thank u

Here my log file:
[link text][1]
and here the screen at the same time of process:

and yes i had canceld the building process fast by now, but it s not the first log (and after i had delete the cache folder like one person said) i have no other cache log.

By now, i have found my own solution to fix it. All to do is to load the older version of Unreal Engine 4 and deinstall the current version (or update if its possible), then load a new project and build the light in the old verion. Install the update or the new version again and then load the current project u want to render and build the light. The error will appear one time , but the swarm agent will build the light and the lightmass volume and it will works. At least i don´t know how long this will be solution but it works by now.