i was in the ubuntu software center, and when i try to install something like OpenJDK, i get an error saying:

Package dependencies cannot be resolved

This error could be caused by required additional software packages which are missing or not installable. Furthermore there could be a conflict between software packages which are not allowed to be installed at the same time.

When i click on "Details" it shows this:

The following packages have unmet dependencies:

openjdk-6-jre: Depends: openjdk-6-jre-headless (>= 6b24-1.11.1-4ubuntu2) but 6b24-1.11.1-4ubuntu2 is to be installed
    Depends: libjpeg8 (>= 8c) but 8c-2ubuntu7 is to be installed
    Depends: libpulse0 (>= 1:0.99.1) but 1:1.1-0ubuntu15.2 is to be installed

How do i fix this, and what's caused this problem in the first place?