Now the day after I tried it again ... After re-doing the whole process a few times yesterday I didn't got it to work, now I try it another time and it worked. Thanks for you help anyway!
So, i got a speaker Sony rdp-x200ipn.
I have an Acer Aspire E17
I can connect my speaker to my laptop via bluetooth fine, when it's connected i can test the speaker and it makes the beep sound. When i start itunes, my speaker plays the sound fine, but when i search for example a youtube video...