If this file doesn't exist: /proc/<pid of crond>/loginuid It's because the kernel doesn't have AUDIT enabled. Set "CONFIG_AUDIT=y" (menuconfig: Under "General setup" enable "Auditing support"), recompile kernel, reboot with new kernel. Now you shouldn't see any more of these messages...
Related message in /var/log/secure: sshd[PID]: pam_loginuid(sshd:session): set_loginuid failed opening loginuid