The participating locator in the composite locator may be invalid or is missing; therefore, it cannot be loaded.
Solution
Open the Composite Address Locator Properties dialog box to reload or remove the problem participating locator.
More information
Participating locators may be missing because of an incorrect path, network, or database connections. You may check the location of the participating locators, or if the network connection is correct. If the participating locator is stored in an enterprise, workgroup, or desktop geodatabase database server, check if the service is up and running.