error with salt-stack(2)

root@testing:/# apt-get install salt-minion
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies.
 salt-minion : Depends: salt-common (= 2015.8.1+ds-1) but it is not going to be installed
               Depends: python-crypto (>= 2.6.1) but it is not going to be installed
               Depends: python-msgpack but it is not installable
               Depends: python-zmq (>= 13.1.0) but it is not going to be installed
               Recommends: dmidecode but it is not going to be installed
               Recommends: debconf-utils but it is not going to be installed
E: Unable to correct problems, you have held broken packages.