The actual sequence of parameters is preset, so if you need to set a message from the variables in SYST, make sure you get the id / type / number sequence correct:


MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno INTO mytext WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.

The system message variables:

SY-MSGID Message-id
SY-MSGTY Message type (E,I,W,S,A,X)
SY-MSGNO Messagenumber
SY-MSGV1 Message variable 1
SY-MSGV2 Message variable 2
SY-MSGV3 Message variable 3
SY-MSGV4 Message variable 4