This bug is fixed with vixie-cron-4.1-8_EL3, available from: http://people.redhat.com/~jvdias/cron/RHEL-3 and should be considered for inclusion in RHEL-3-U7 .
Fixed with vixie-cron-4.1-10.EL3, currently in RHEL-3-U7 with errata RHSA-2005:0117.