Image Annotator error w/ Omeka 1.5.3

Image Annotator was behaving itself for a long time but is now coughing up these error messages whenever we try to run it.

Zend_Controller_Dispatcher_Exception
Invalid controller specified (image)
#0/var/www/html/omekasites/EarlyCaribbeanArchive/application/libraries/Zend/Controller/Front.php(954): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))

#1/var/www/html/omekasites/EarlyCaribbeanArchive/application/libraries/Zend/Application/Bootstrap/Bootstrap.php(97): Zend_Controller_Front->dispatch()

#2/var/www/html/omekasites/EarlyCaribbeanArchive/application/libraries/Zend/Application.php(366): Zend_Application_Bootstrap_Bootstrap->run()

#3/var/www/html/omekasites/EarlyCaribbeanArchive/application/libraries/Omeka/Core.php(165): Zend_Application->run()

#4 /var/www/html/omekasites/EarlyCaribbeanArchive/index.php(28): Omeka_Core->run()

#5 {main}

Can you please provide some suggestions as to how fix this?

And thank-you in advance for any help you can provide.