For increased security, At Ease will move the "Find By Content" extension from the Extensions folder to the Secured Items folder when a user with less than full Finder access logs on. If an administrator bypasses At Ease, using Command-Shift-Escape while at the log in screen, immediately after a Panels' user has logged out, the "Find by Content" extension is not moved back into the Extensions folder. This will cause the error mentioned above after launching Sherlock.
Note: If the Administrator logs into At Ease, and selects a Finder workgroup, the extension is moved back to its proper place. If you see this error message frequently, make a Finder workgroup that you, as the Administrator has access to. You should only need to bypass At Ease for occasional maintenance and configuration changes, such as changing printer settings or installing new software.