What does the error message "Alarm: initial startup, there is material in the assembly line machine code of KM-ASSYM3-04 error id of 33" mean?

What is the name of the KMs machine code that contains the error?
To fix the error described as Alarm: initial startup, there is material in the assembly line, you'll need to identify the source of the material and clear it from the assembly line. This may require adjusting your manufacturing processes or stopping production