Security warning with sshd

[Pat Maddox]

In my recent security email, I got the following errors:
cantona.dnswatchdog.com login failures:
Aug 20 02:37:19 cantona sshd[9444]: fatal: Write failed: Operation not permitted
Aug 20 04:30:42 cantona sshd[16142]: fatal: Write failed: Operation
not permitted
Aug 20 21:21:51 cantona sshd[45716]: fatal: Write failed: Operation
not permitted

So three questions: What is it?  Should I be worried?  How can I fix it?

Thanks,
Pat