The status of your system is being checked to ensure that all enabled features are available, that the mail server is properly configurated, and that quotas are active …
This is some kind of “virtual” dedicated server, I presume? Some types of virtual server have this problem, I believe, and you’ll have to disable disk quotas as they don’t work on this type of system (not our fault, just a fact of life on this type of virtual server–I think you can still get disk usage reports via du on this type of system).