From searchkicks' github readme
For Elasticsearch 0.90, use version 0.6.3 and this readme.
Consider either updating elasticsearch on your machine, you can download it from http://www.elasticsearch.org/overview/elkdownloads/, if you are using ubuntu the easiest way is to download and install DEB package, for RHEL/fedora (and similar) RPM package, for OS X either zip/tar archive and follow instructions.
Alternatively for OS X you can use
brew install elasticsearch
according to this http://red-badger.com/blog/2013/11/08/getting-started-with-elasticsearch/
or consider using older version of searchkick (not recommended) :)