EQA1493E There is no variable named character string, and if it is meant to be a built-in function, remember built-in functions are allowed only in expressions.

Explanation

A variable could not be found. Its name, however, is also that of a PL/I built-in function. If the built-in function was intended, it is not in the correct context. Note that in z/OS® Debugger, pseudo-variables cannot be the target of assignments.