Sensu OpsGenie Error

gistfile1.txt

"timestamp":"2013-03-01T15:32:21.396291+0000","message":"/etc/sensu/handlers/opsgenie.rb:51:in `post_to_opsgenie': undefined method `[]' for nil:NilClass (NoMethodError)","level":"info"}
{"timestamp":"2013-03-01T15:32:21.396685+0000","message":"\tfrom /etc/sensu/handlers/opsgenie.rb:46:in `create_alert'","level":"info"}
{"timestamp":"2013-03-01T15:32:21.397108+0000","message":"\tfrom /etc/sensu/handlers/opsgenie.rb:22:in `handle'","level":"info"}
{"timestamp":"2013-03-01T15:32:21.397329+0000","message":"\tfrom /usr/lib/ruby/1.8/timeout.rb:67:in `timeout'","level":"info"}
{"timestamp":"2013-03-01T15:32:21.397518+0000","message":"\tfrom /usr/lib/ruby/1.8/timeout.rb:101:in `timeout'","level":"info"}
{"timestamp":"2013-03-01T15:32:21.397894+0000","message":"\tfrom /etc/sensu/handlers/opsgenie.rb:19:in `handle'","level":"info"}
{"timestamp":"2013-03-01T15:32:21.398056+0000","message":"\tfrom /usr/lib/ruby/gems/1.8/gems/sensu-plugin-0.1.6/lib/sensu-handler.rb:41","level":"info"}
{"timestamp":"2013-03-01T15:32:21.398219+0000","message":"\tfrom /etc/sensu/handlers/opsgenie.rb:49","level":"info"}