There are two ways you can increase the "maximum number of output members" in ADROUT
1. Change the directory name and the number of outputs...
run VLSUTIL format on ADROUT / SCPSUTIL INIT
Note: Once you run the FORMAT/INIT, your old prints will no longer be available. My suggestion would be to print out any output that you still need.
2. Run SCPSUTIL function EXPANDDIR
Note: You will need to make sure that all activity is halted on ADROUT so recommendation is to close the file before you run EXPANDDIR.