error while loading test plan

[sushmatshetty]

Hi,
I am trying to open the example test plan and gettng below error:

Problem loading XML from:'/Users/sushma.shetty/kafka_load/kloadgen-master/Example-Test-Plan.jmx'.
Cause:
CannotResolveClassException: com.sngular.kloadgen.config.kafkaheaders.KafkaHeadersConfigElement

Detail:com.thoughtworks.xstream.converters.ConversionException:
---- Debugging information ----
cause-exception : com.thoughtworks.xstream.converters.ConversionException
cause-message :
first-jmeter-class : org.apache.jmeter.save.converters.HashTreeConverter.unmarshal(HashTreeConverter.java:66)
class : org.apache.jmeter.save.ScriptWrapper
required-type : org.apache.jmeter.save.ScriptWrapper
converter-type : org.apache.jmeter.save.ScriptWrapperConverter
path : /jmeterTestPlan/hashTree/hashTree/hashTree/com.sngular.kloadgen.config.kafkaheaders.KafkaHeadersConfigElement
line number : 29
version : 5.5