The e4 tools master move on, so that they can only be used for Eclipse 4.4 (Luna). You find the latest Kepler version of the e4 tools under the following p2 update site:
p2 update site for Eclipse 4.3 (Kepler)
You find a continous integration build for Luna under the following p2 update site>
p2 update site for Eclipse 4.4 (Luna)
You find the tools also under the official Eclipse e4 download site with lists all available update sites, but I sometimes find it easier to remember a fixed link.
I hope this helps.