What version of Kibana and Elasticsearch are you targeting? I had a
similar problem today after upgrading to Elasticsearch 1.0 on Friday,
thought Kibana was still working fine (page loaded and the graphs + data
still displayed) until I tried adding a filter at which point it started
spitting out error messages.
I upgraded Kibana to version 3 milestone 5 (the current latest version)
and the problem went away.