cassandra transport exception

gistfile1.txt

/opt/ruby/ruby-1.9.2-p290/lib/ruby/gems/1.9.1/gems/thrift-0.8.0/lib/thrift/transport/socket.rb:109:in `read': CassandraThrift::Cassandra::Client::TransportException
        from /opt/ruby/ruby-1.9.2-p290/lib/ruby/gems/1.9.1/gems/thrift-0.8.0/lib/thrift/transport/base_transport.rb:87:in `read_all'
        from /opt/ruby/ruby-1.9.2-p290/lib/ruby/gems/1.9.1/gems/thrift-0.8.0/lib/thrift/transport/framed_transport.rb:104:in `read_frame'
        from /opt/ruby/ruby-1.9.2-p290/lib/ruby/gems/1.9.1/gems/thrift-0.8.0/lib/thrift/transport/framed_transport.rb:69:in `read_into_buffer'
        from /opt/ruby/ruby-1.9.2-p290/lib/ruby/gems/1.9.1/gems/thrift-0.8.0/lib/thrift/protocol/binary_protocol.rb:190:in `read_i32'
        from /opt/ruby/ruby-1.9.2-p290/lib/ruby/gems/1.9.1/gems/thrift-0.8.0/lib/thrift/protocol/binary_protocol.rb:116:in `read_message_begin'
        from /opt/ruby/ruby-1.9.2-p290/lib/ruby/gems/1.9.1/gems/thrift-0.8.0/lib/thrift/client.rb:45:in `receive_message'
        from /home/paul/.bundler/ruby/1.9.1/cassandra-f67bc0bc4d64/vendor/0.8/gen-rb/cassandra.rb:251:in `recv_batch_mutate'
        from /home/paul/.bundler/ruby/1.9.1/cassandra-f67bc0bc4d64/vendor/0.8/gen-rb/cassandra.rb:243:in `batch_mutate'
        from /opt/ruby/ruby-1.9.2-p290/lib/ruby/gems/1.9.1/gems/thrift_client-0.8.1/lib/thrift_client/abstract_thrift_client.rb:150:in `handled_proxy'
        from /opt/ruby/ruby-1.9.2-p290/lib/ruby/gems/1.9.1/gems/thrift_client-0.8.1/lib/thrift_client/abstract_thrift_client.rb:60:in `batch_mutate'
        from /home/paul/.bundler/ruby/1.9.1/cassandra-f67bc0bc4d64/lib/cassandra/protocol.rb:7:in `_mutate'
        from /home/paul/.bundler/ruby/1.9.1/cassandra-f67bc0bc4d64/lib/cassandra/cassandra.rb:459:in `insert'
        from /home/paul/spikes/cassandra_tests/cassandra_store.rb:43:in `set'
        from loader.rb:46:in `block in <main>'
        from /opt/ruby/ruby-1.9.2-p290/lib/ruby/1.9.1/csv.rb:1768:in `each'
        from /opt/ruby/ruby-1.9.2-p290/lib/ruby/1.9.1/csv.rb:1370:in `parse'
        from loader.rb:43:in `<main>'