root@server11:~# apt-get install apache2 apache2-mpm-prefork apache2.2-common
Reading package lists... Done
Building dependency tree
Reading state information... Done
apache2-mpm-prefork is already the newest version.
apache2.2-common is already the newest version.
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:
 apache2 : Depends: apache2-mpm-worker (= 2.2.16-6) but it is not going to be installed or
                    apache2-mpm-prefork (= 2.2.16-6) but 2.2.16-6+squeeze1 is to be installed or
                    apache2-mpm-event (= 2.2.16-6) but it is not going to be installed or
                    apache2-mpm-itk (= 2.2.16-6) but it is not going to be installed
           Depends: apache2.2-common (= 2.2.16-6) but 2.2.16-6+squeeze1 is to be installed
E: Broken packages
root@server11:~#