ok, im gonna reply in english, my german isnt the best, but i can read it
I think what happens here, it goes through the loop normally. and comes to a point where you = null. then you set i to 0, and it quits the if that reads i == 1.
it comes in the other branch, and continues the ent_next, even though it was empty.
I think what you need there is simply: you = null;

that's what came to mind when reading through it real quick.
anyway, worth a try!

regards,