2123964 - CopyOpening package is aborted and dump GETWA_NOT_ASSIGNED is generated in backend

When user creates a CopyOpening business rule and executes it by package, the package finally "aborted" and in backend ST22, a dump happens as following:

Category               ABAP Programming Error
Runtime Errors         GETWA_NOT_ASSIGNED
ABAP Program           CL_UJP_COPYOPENING============CP
Application Component  EPM-BPC-NW-TDL

Error in the ABAP application program.

The current ABAP program "CL_UJP_COPYOPENING============CP" had to be
 interrupted because it contains
a statement that cannot be executed.

Error analysis
    You attempted to access an unassigned field symbol
    (data segment "-1").

Information on where terminated
    Termination occurred in the ABAP program "CL_UJP_COPYOPENING============CP" -
     in "PREPARE_OPENING".
    The main program was "UJK_SCRIPT_LOGIC_TESTER ".

    In the source code you have the termination point in line 592
    of the (Include) program "CL_UJP_COPYOPENING============CM004".

EPM, BPC NW, Business Planning and Consolidation for NetWeaver, CopyOpening, aborted, CL_UJP_COPYOPENING============CP, GETWA_NOT_ASSIGNED, You attempted to access an unassigned field symbol, data segment "-1", PREPARE_OPENING, UJK_SCRIPT_LOGIC_TESTER, FLOW, dimension, carry forward , KBA , EPM-BPC-NW-ADM-TDL , Business Rules , Problem