Upload function BAPI_REQUIREMENTS_CREATE has error

Dear All,

I used BAPI function to upload Demaind (MD61). It is BAPI_REQUIREMENTS_CREATE and BAPI_REQUIREMENTS_CHANGE. Sometimes, I got error message: '6U 100: Error at insert Table

PBHI', and error sent to my Workplace. Sometimes, It is ok with the same data. It is not stable.

I also checked in SM13, error at function module: PLANBEDARF_UPDATE. It is SAP standard function. Pls tell me why this error occurs.

Thanks so much. I will mark good point for good answer.