Error message with "/i" command: I have created an InputScript with the statement:

Enter onerror="/i"

Is it somehow possible to create an error message on the screen to which I return?

Yes, this is possible. Use

Enter onerror=Continue

ReturnValues " ...., process=errormessage.txt"

Enter "/i"

to process an InputScript on the screen that you left with the "/O" command.