Ouch. You may want to open a case with Cisco TAC on this one. Was there anything that happened, any change, on that date that you know of?
One thing you can try (TAC will probably have you do this anyways) and it's pretty painless and won't mess up anything worse is to reset the five core account passwords. Make absolutely SURE you do this after hours.
You must be on the publisher CCM in order to do this; here's the instructions, directly from Cisco:
Step 1: Log on as the local Administrator on the Publisher.
Step 2: Using Explorer, browse to C:\Program Files\Cisco\Bin and launch AdminUtility.exe.
Step 3: Within the User Password field, input the local Administrator password and click
OK.
Step 4: Select the check-box for at the top of the tree which should correlate to the DNS
name of the Publisher.
Step 5: Select Options from the menu, and Set New Password.
Step 6: Input your 1 - 15 character alphanumeric password phrase that will be used to
generate the complex passwords for each local account and service. Re-enter the string
within the next field for verification and click OK.
Step 7: Highlight all systems within the cluster and click Update Server Password. You
will receive a warning message informing you that this will take down all systems with the
cluster and could take a significant amount of time. Click OK.
Step 8: When completed, for each system you will see that the Update was successful.
Click EXIT once all systems within the cluster have successfully updated.
Step 9: Close the AdminUtility window.
TMH