Dependency Error == Unable to Install Anything Else

[Scarletdown <scarletdown@gmail.com>]

I'm trying to install a new kernel (going from 2.8.18-3-k7 to
2.6.22-2-k7) so that I can update my video drivers.  However, I keep
getting this annoyance that causes anything I try to install to fail:

You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies.
  gnupg-agent: Depends: libpth20 (>= 2.0.7-2) but it is not going to be
installed
  gpgsm: Depends: libpth20 (>= 2.0.7-2) but it is not going to be
installed
  libgpgme11: Depends: libpth20 (>= 2.0.7-2) but it is not going to be
installed


Of course, I did the suggested apt-get -f install.  Apt tried to install
libpth20, but failed with this error:

dpkg: error processing /var/cache/apt/archives/libpth20_2.0.7-8_i386.deb
(--unpack): trying to overwri /usr/lib/libpth.so.20.0.27 which is also
in package libpth2.

So, I am at a standstill here.  How do I fix this and make my system
useable again?