Fix identification of identifier for error report. Setting it to null if the previous attempt was successfull already obviously was a flaw. Using the wrong key HAUPTPROBEN_NR probably could have been avoided by usage of appropriate constants.

{
    "land.kommentar_m": [{
        "id":1000,
        "erzeuger":"06010",
        "datum":"2012-05-08 11:00:00",
        "text":"Testkommentar",
        "messungs_id":1200
    }]
}