RSVP “Unknown session type”

Resource ReserVation Protocol (RSVP): PATH Message. 
    RSVP Header. PATH Message. 
        0000 .... = RSVP Version: 0
        .... 0000 = Flags: 0x00
        Message Type: PATH Message.  (1)
        Message Checksum: 0xf7fa [incorrect, should be 0xf7fa]
        Sending TTL: 0
        Message length: 0
Unknown session type

Is the "Unknown session type" a separate issue from the incorrect Checksum?

What does "Unknown session type" mean?

Any help would be appreciated.