Problema para instalar acroread 7

[Manuel Campos]

Hola, estoy intentando instalar acroread7, cuando hago apt-get install
acroread, me da el siguiente error:

root en lindogatito:~ # apt-get install acroread
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:
  acroread: Depends: libc6 (>= 2.3.2.ds1-21) but 2.3.2.ds1-20ubuntu13
is to be installed
E: Broken packages


Estoy usando todos los repositorios de ubuntu, y los de merillat para
los plugins audio/video. Que puedo hacer?

Gracias,
Manu.