I have a server application that creates a Bus on the dbus and after some minutes of running I got an error that I have never seen before. Did you have an idea whats wrong?<
This should be fixed in curl 7.32.0 according to the Debian changelog where threaded DNS resolver has been implemented. The Debian package is in unstable and can be found here.
For Ubuntu 12.04 -> 13.04 you can use this PPA.
sudo apt-add-repository ppa:jaywink/curldebian
sudo apt-get update && sudo apt-get upgrade
Ubuntu 13.10 includes curl 7.32 so should not have this problem.