The problem is solved. It worked the right way. I waqs just confused about a
message on the boot screen, which dissapeared after a short while.
The only thing thats confusing me right now, is the fact, that my
boot-up-speed is not faster as before e4rat. The screen stays a very long
time black and then the boot messages appear. I did everything the right way
as you mentioned and how it is explained here:
http://www.howtogeek.com/69753/how-to-cut-your-linux-pcs-boot-time-in-half-with-e4rat/
Can you help me with this? Thanks!
(Sorry for my bad english, I'm from germany :)