despues de:

apt-get update
apt-get upgrade


Setting up gs-gpl (8.50-1.1) ...

debian:/home/alex# apt-get -f install
Reading Package Lists... Done
Building Dependency Tree... Done
0 upgraded, 0 newly installed, 0 to remove and 463 not upgraded.


debian:/home/alex# /usr/bin/apt-get install flashplugin-nonfree
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:
  flashplugin-nonfree: Depends: gsfonts-x11 but it is not going to be installed
E: Broken packages
debian:/home/alex#        

debian:/home/alex# uname -a
Linux debian 2.4.27-2-k7 #1 Wed Nov 30 22:12:04 JST 2005 i686 GNU/Linux