The version of the DLTK Ruby tools you have installed is 2.0.0 which is very old (the current version in the Kepler repo is 5.0.0). ShellEd declares that it requires DLTK version 4.0.0 or higher, so you just need to upgrade to the latest DLTK Ruby version. That should be easy to do by selecting the Kepler repo when doing Install New Software.
It looks like the DLTK Mylyn Integration feature does not exist any more so you'll have to let it be uninstalled. That doesn't affect Mylyn in general, which should remain intact.