Why do I see warnings in multipath command output referencing "invalid keyword" after updating to RHEL 5 Update 6?

Issue

• When the command multipath -ll is run, following error is seen:

       # multipath -ll
         multipath.conf line 93, invalid keyword: polling_interval
  

• The followng errors are also seen when running the multipath command.  The  system was also recently upgraded to RHEL 5.6

  # multipath -l
  mulipath.conf line 18, invalid keyword: user_friendly_name
  mulipath.conf line 21, invalid keyword: devnode_blacklist
  mulipath.conf line 22, invalid keyword: devnode
  mulipath.conf line 23, invalid keyword: devnode
  mulipath.conf line 24, invalid keyword: devnode
  mulipath.conf line 25, invalid keyword: }
  mulipath.conf line 30, invalid keyword: path_checker