Diagnosis
The business partner BAPIs were called up incorrectly. The indicatorIV_X_SAVE was given differing settings when the modules were called.
Within a LUW, the indicator must be consistently set or not set.

System Response
The indicator IV_X_SAVE should be set or not set once off. Up to COMMITWORK the content of the field may not be changed, as problems willotherwise occur with the internal memory, thus leading to runtimeerrors.