Photoshop CS# and Elements both have a feature that allows you to tell Photoshop where it can find additional plug-ins. By default Photoshop only looks in its own Plug-ins folder, but by using this option, you can tell it where else to look. The downside is when you tell it to look in its own plug-ins folder a second time. Doing so could produce the following error.
You can find out if your preferences are pointing to Photoshops plug-ins folder by clicking Photoshop > Preferences > Plug-ins. You will see this screen. If the option is checked, and it is pointed back to the default Photoshop plug-ins folder, un-check this option and click OK.
Once you click OK, just quit Photoshop and relaunch it. You should no longer be receiving this error. If the path is not a default Photoshop plug-ins folder, make sure to check in the listed directory for any additional Autolayer files.