Diagnosis
If you change a variable item to a fixed item, it is automaticallyinserted as the last fixed item. The new item is automatically given anumber that is between the item numbers of the last fixed item and thefirst variable item.
If the items are changed frequently the number of the last variableitem may follow on directly from the number of the first fixed item.

System Response
You cannot change a variable item to a fixed item.

Procedure
Adjust the item numbers so that the number of the first variable itemdoes not follow on directly from the number of the last fixed item, andperform the action again.