What do you mean by "copied"? Do you mean you had it installed on another computer and moved it to the new one? If so, I'm afraid you made a lot of extra work for yourself.
You can never, never, never copy PSE or restore it from Time Machine, or use Migration Assistant. PSE is not a tidy package app in accordance with the apple developer guidelines. The PSE installer is more like a blast of buckshot, strewing stuff all over your hard drive and you can't ever find all the necessary bits and pieces.
You will need to download and run this, then manually remove what you can find. Not only from the applications folder but from the library at the top level of your hard drive>application support>adobe. In 10.7 and higher this library isn't exactly hidden, but it's hard to see. Easiest way is to go to finder preferences>sidebar and turn on Hard disks under Show in Sidebar, then open a new finder window and click on your hard drive in the list on the left side.
If you migrated from an earlier version of OS X, also go to your username>library>preferences and delete:
Adobe Photoshop Elements 11 paths
Adobe Photoshop Elements 11 settings
and any lockfiles with the same names
That library is hidden in 10.7 and 10.8. To see it, option-click the Go menu in the Finder. While you're in the library, go to the Saved application states folder and delete anything pertaining to PSE.
When you need PSE on another computer, always install it fresh.
Are you sure you're understanding the message? In any case if you brought it over, you can put it in the trash, since it wasn't properly installed to begin with, but be sure you can't run the cleaner first--make certain the dialog box isn't warning you that your installation will be damaged. If that's what it says, no problem, since it already is.