Katherine Jackson -- LIVID Over Unpaid Workers At MJ Tribute Concert

Katherine Jackson is upset she had anything to do with the recent Michael Jackson Tribute concert -- telling TMZ, Global Live better take care of the workers they allegedly failed to pay.

Scores of crew members recently went on Twitter to slam Global Live -- the concert producers -- and insist the company stiffed them after they busted their asses for the event.

Katherine's lawyer tells us, "After Mrs. Jackson did all she could to help promote and make this a great event for all of Michael's fans, she is extremely displeased to hear that concert promoters have allegedly failed to pay their bills."

The lawyer adds, "Katherine is hoping that they step up and take care of their obligations." So far no word back from Global Live.