We've just had a similar problem with one of our servers... it turns out that "rc=122" is an error code indicating a quota problem.
Sure enough, there was an account over its quota: "WHM -> Account Information -> Show Accounts over Quota". We fixed the issue by increasing the user's quota & freeing up some disk space. No more error messages in the log & no need to disable SELinux
I hope this solution helps (& is worth having dug up an relatively old thread!)
it is a known fact that selinux must be disabled on cpanel servers. first of all it breaks postgresql databases, second gets a ton of errors in the cpanel, and third of all, does not provide the real security that a webserver should have.
i am using grsecurity, and for all i know and all the people out there who are using it, they know as well that this is the thing.