I have the same problem, with Release 6.0.7_GA_2473.RHEL5_64_20100616202447 RHEL5_64 NETWORK edition.
I can run a zmschedulebackup -R -a all f "0 1 * * 6" but I have same problem as you if I run a zmschedulebackup -R -a all i “0 1 * * 0-5” or a zmschedulebackup -R -a all d 15d “0 0 * * *”
Same problem with zmschedulebackup -A , after zmschedulebackup -F |