Field symbol has not been assigned yet.

What happened?
    Error in the ABAP Application Program

    The current ABAP program "ZTESTPROGRAM" had to be terminated because of it
     has
    come across a statement that unfortunately cannot be executed.
What can you do?
    Note down which actions and inputs caused the error.


    To process the problem further, contact you SAP system
    administrator.

    Using Transaction ST22 for ABAP Dump Analysis, you can look
    at and manage termination messages, and you can also
    keep them for a long time.
Error analysis
    An attempt was made to access a field symbol that has not been assigned
    yet (data segment number "-1").

    That error occurs if
    - a typed field symbol is addressed before it has been set with ASSIGN,
    or
    - a field symbol is addressed that points to a row in an internal table
    that has been deleted, or
    - a field symbol is addressed that was previously reset using UNASSIGN,
    or that pointed to a local field that no longer exists, or
    - a parameter of a global function interface is address, although the
    the corresponding function module is not active (is not in the list of
    active calls). The list of active calls can be taken from this short
    dump.