Thank you, pavroo,
oh, I didn't know that problem is by the TeamSpeak-people.
Hm, do you know, if Sparky has an alternative one? ....Maybe even preinstalled?
...Or reachabel by using the Terminal commands
sudo apt-get install 'programm-name'
...Ahh, sorry, this was a stupid question...
I see now, that in the APTus-extra tool, you can get Skype (with one click)