Regarding the error msg - "INVALID DATA STATUS" returned by the BAPI

I use a BAPI - "BAPI_PBSRVAPS_GETDETAIL2" - to download key figure values from planning book in APO.

But at times the bapi returns a message "Invalid data status" ...

Any idea as to why this error message is returned??

what is the error/erason that causing this message ?

Kindly help... wud really appreciate helpful solns..