I'm using ubuntu 10.10 and recently my package manager has stopped working because of some problems with dependencies or something. I can't upgrade, install or uninstall anything at all. This is a huge problem. I couldn't find a solution to this with google so I'm asking here for help.

This is what apt-get -f install outputs

LANG=en_US.UTF-8 sudo apt-get install -f
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following package was automatically installed and is no longer required:
  firefox-4.0-core
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
1 not fully installed or removed.
After this operation, 0B of additional disk space will be used.
Setting up openjdk-6-jre-headless (6b20-1.9.5-0ubuntu1) ...
update-alternatives: error: alternative path /usr/lib/jvm/java-6-openjdk/jre/bin/java doesn't exist.
dpkg: error processing openjdk-6-jre-headless (--configure):
 subprocess installed post-installation script returned error exit status 2
Errors were encountered while processing:
 openjdk-6-jre-headless
E: Sub-process /usr/bin/dpkg returned an error code (1)