Apache kafka listener listens less messages than produced

[Ratha v]

I use old kafka consumer and producer(v 0.8x)
When i produce 10 messages i get only 6 messages..Is there anything wrong
in my listener .properties?

I start listener first then producing ..

*Listener properties*

    enable.auto.commit=true
    auto.commit.interval.ms=101
    session.timeout.ms=7000

key.deserializer=org.apache.kafka.common.serialization.StringDeserializer
    value.deserializer=com.xx.FileSerializer
    zookeeper.connect=zookeeper.xx.com\:2181
    heartbeat.interval.ms=1000
    auto.offset.reset=smallest
    serializer.class=com.xxx.FileEncoderDecoder
    bootstrap.servers=kafka.xxx.com\:9092
    group.id=test
    consumer.timeout.ms=10000
    fetch.min.bytes=1
    receive.buffer.bytes=262144

-- 
-Ratha
http://vvratha.blogspot.com/