I found a solution to my problem. It appears like the QMC may have a column limit with respect to being able to perform the "Open Document" action. I simply temporarily reduced the number of columns in the "flat_file" table (making sure to keep those needed to set up the scheduled job), and then ran and saved the .qvw. I was now able to perform the "Open Document" function on the .qvw with the reduced column "flat_file" table and set the scheduled job up using the desired fields for reduction and distribution. Finally I went back to the .qvw and loaded all columns back into the "flat_file" table. The scheduled job appears to running fine.
Has anyone else run into this - does the QMC have a limits on what it will open when setting up tasks on a .qvw?