If you are seeing this error in your Naemon debug log, one possible reason why your checks aren't running is that the "check_period" they are configured to use either disqualifies the checks directly, or has an "exclude" value that disqualifies the checks. Try removing any exclusions and verify that your time periods are correctly configured.
This error can also be caused by the host or service being checked by an INACTIVE poller. Make sure your cluster is ACTIVE across the board, and if necessary, re-configure takeover options for merlin and/or hostgroup memberships.
If you believe the node is denying these checks in error, one thing you may want to test is to mark all these objects in your primary master in the web GUI, click the checkbox icon at the top right and disable checks for all the marked services.
After the checks have been disabled, try doing the same thing but now enable the checks. Wait a while, and see if they run as expected according to the schedule.