When creating the Queries for the Query Scheduler, it is very important that you use only current month files. When you set up the automation process, CU*BASE allows you to indicate whether you would like the Scheduler to automatically substitute the proper file name to pull from the most recent month-end. 

Query Scheduler will not work properly if end-of-month file names (ExxMMYY1, for example) are used in the original Query saved in your QUERYxx library. You may need to set up separate Queries to be used only by the Query Scheduler.