Solution: re-install SAP Logon GUI
Remove - reboot - re-install.
http://sap.ittoolbox.com/groups/technical-functional/sap-basis/err-message_type_x-for-sapgui-1470853
Runtime Errors MESSAGE_TYPE_X
METHOD FLUSH .
* ...
data: rc like sy-subrc, msgli like sy-msgli.
CALL FUNCTION 'AC_FLUSH_CALL'
EXPORTING
SYSTEM_FLUSH = ' '
IMPORTING
MESSAGE_NR = rc
MESSAGE_TEXT = msgli.
sy-subrc = rc.
sy-msgli = msgli.
CASE SY-SUBRC.
WHEN 0.
WHEN 1.
* system_error
MESSAGE ID 'CNDP' TYPE 'X' NUMBER 007 RAISING CNTL_SYSTEM_ERROR.
WHEN 2.
* method_call_error
MESSAGE ID 'CNDP' TYPE 'X' NUMBER 006 RAISING CNTL_ERROR.
WHEN 3.
* property_set_error
MESSAGE ID 'CNDP' TYPE 'X' NUMBER 006 RAISING CNTL_ERROR.
WHEN 4.
* property_get_error
MESSAGE ID 'CNDP' TYPE 'X' NUMBER 006 RAISING CNTL_ERROR.
WHEN OTHERS.
RAISE CNTL_ERROR.
ENDCASE.
ENDMETHOD.