When attempting to install the package vncserver via the 'apt-get install vncserver' command it returns the following error stating:

Reading Package Lists... Done
Building Dependency Tree... Done
Package vncserver is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or is only available from another source
E: Package vncserver has no installation candidate

According to what I determined from reading the error and searching for similiar errors I've determined that I need to download the package from an alternate location. Can anyone tell me what that location is and if there is anything special I need to do to install a VNC server for my Knoppix live cd?