ERROR # 173 and ERRORS DURING ELEMENT QUALITY CHECK

Hello,

I get two errors in my model. One of them is  ''*** ERROR # 173 *** A dependent d.o.f. defined more than once in rigid element entry. GRID ID = xxx component = 1''. I checked my RBE2 elements but I think there is no problem, I can't find the problem. Also, I get ''PROGRAM STOPPED: ERRORS DURING ELEMENT QUALITY CHECK'' error. Then, I review my elements for this error but my tet-collepse is 0. There is no problem for my elements. Where are the mistakes, where am I doing wrong? Please help me, its to important for me.