I'm in the woods in Chapter 2 (where dark elves are) , and I have problem returning to north.
I get to Y crossing, but I can not move on path - It's like there it is invisible barrier or wall, that prevents me from moving on the path. I did draw Blue line - as it seams to be border, and red arrow, where I would like to move. How can I get rid of this bug?

I know exactly where you are and I had the same problem when I bought Sacred on CD. I resolved it by re-installing the game. Make sure to copy your characters to a temp directory for safety, then just uninstall the game and re-install it. It worked for me.