Yep, did this and now have issue with Add Complex.
Wait 1 hour and then update your Kloxo-MR 7.0 with 'yum clean all; yum update -y'.
I deleted all the cronjobs and "Add Simple" it works. It runs every minute. Then I deleted that simple cron and Add Complex. It stops working. I select cron from list and then noticed that the minutes doesn't take. I update it to --all-- then it works. It runs every minute. But it will not save any other changes.
example: 1,2,3,15,32,45,etc. when click update it will goes back to 0.
If change to --all-- then it will stick.
By the way, no more error message.
"Adding crontab has failed due to . Please delete this cron and add it again."