Question : Cisco Aironet 1100 - WDS Authentication Issue

I am getting the following in the Event Logs of one of my Aironet 1100's: Error AP Authentication to the WDS failed.

I didn't setup the Wireless Infrastructure at this site, so I'm not entirely sure how everything is put together. But, I do know that hosts trying to connect to the Private SSID on the AP are not able to successfully authenticate using their domain credentials, which is something they can do in other parts of the building.

Answer : Cisco Aironet 1100 - WDS Authentication Issue

The only place that message shows up is in the IOS docs... e.g.
http://www.cisco.com/en/US/docs/wireless/access_point/12.3_4_JA/configuration/guide/s34err.html#wp1009096

Which IS for the 1100, for what it's worth... 6th message down from where that link leads - it says:
The access point failed to authenticate to the WDS device because the username or password were incorrect.
Resolution:
Correct the username and password configuration on either the access point or the authentication server.

So, if it's an AP acting as a WDS-connected repeater, it sounds like its settings have either gotten wiped or corrupted.
And if acting as a repeater, it would not be connected to the controller (if there is one) to download its setups at boot time (as the lightweight APs do). That message appears in the 12.3 (3) JA docs, too, but I did not find it elsewhere.