"A converted for this file is not installed. Please heck your datatypes_conf.xml file."

How exactly do I find out which converted files I am missing?  

This information isn't easy to find yet, so I've created a card for it: https://trello.com/c/E3ReiSVU

If you haven't modified your datatypes_conf.xml, you can copy datatypes_conf.xml.sample to datatypes_conf.xml and the converter error should go away.

FYI, the complete instructions for setting up visualizations in Galaxy can be found here:

http://wiki.galaxyproject.org/Visualization%20Setup

Let us know if you run into other issues.

Best,
J.