Cause
This error occurs in one of the following conditions.
If your application code attempts to assign to a system variable. The values of system variables are maintained internally by JADE, and you cannot assign a value to them in your application code.
If your application code passes a system variable type guard expression (for example, self.Customer) as a parameter to another method where that parameter is defined as usage io or output. This is not permitted because the other method can assign to this parameter.
When an assignment cannot be made to the variable used as the control variable in a
Action
Change your application code to remove the invalid assignment.
If the error was reported on the passing of a parameter, it may be possible to change the usage of that parameter to constant (the default) or input in order to resolve the error.
If the error was reported against the control variable of a foreach instruction, use a local variable as the control variable.