valkyrie:/etc/apt# aptitude upgrade
Reading Package Lists... Done
Building Dependency Tree
Reading extended state information
Initializing package states... Done
Reading task descriptions... Done
The following packages have been kept back:
  exim4-base libpam-modules libpam-runtime passwd perl-base
0 packages upgraded, 0 newly installed, 0 to remove and 5 not upgraded.
Need to get 0B of archives. After unpacking 0B will be used.
Reading Package Lists... Done
Building Dependency Tree
Reading extended state information
Initializing package states... Done
Reading task descriptions... Done
valkyrie:/etc/apt# apt-get install exim4-base
Reading Package Lists... Done
Building Dependency Tree... 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.

Since you only requested a single operation it is extremely likely that
the package is simply not installable and a bug report against
that package should be filed.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
  exim4-base: Depends: libc6 (>= 2.7) but 2.3.2.ds1-22sarge6 is to be installed
              Depends: libdb4.8 but it is not installable
              Depends: lsb-base (>= 3.0-6) but it is not going to be installed
E: Broken packages
valkyrie:/etc/apt# apt-get install libpam-modules
Reading Package Lists... Done
Building Dependency Tree... 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.

Since you only requested a single operation it is extremely likely that
the package is simply not installable and a bug report against
that package should be filed.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
  libpam-modules: PreDepends: libc6 (>= 2.4) but 2.3.2.ds1-22sarge6 is to be installed
                  PreDepends: libdb4.8 but it is not installable
                  PreDepends: libselinux1 (>= 2.0.85) but it is not going to be installed
E: Broken packages
valkyrie:/etc/apt# apt-get install libpam-runtime
Reading Package Lists... Done
Building Dependency Tree... 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.

Since you only requested a single operation it is extremely likely that
the package is simply not installable and a bug report against
that package should be filed.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
  libpam-runtime: Depends: debconf (>= 1.5.19) but 1.4.30.13 is to be installed
                  Depends: libpam-modules (>= 1.0.1-6) but 0.76-22 is to be installed
E: Broken packages
valkyrie:/etc/apt# apt-get install passwd
Reading Package Lists... Done
Building Dependency Tree... 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.

Since you only requested a single operation it is extremely likely that
the package is simply not installable and a bug report against
that package should be filed.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
  passwd: Depends: libselinux1 (>= 1.32) but it is not going to be installed
          Depends: debianutils (>= 2.15.2) but 2.8.4 is to be installed
E: Broken packages
valkyrie:/etc/apt# apt-get install perl-base
Reading Package Lists... Done
Building Dependency Tree... 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.

Since you only requested a single operation it is extremely likely that
the package is simply not installable and a bug report against
that package should be filed.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
  perl-base: PreDepends: libc6 (>= 2.4) but 2.3.2.ds1-22sarge6 is to be installed
             PreDepends: dpkg (>= 1.14.20) but 1.10.28 is to be installed
E: Broken packages