Problem with multi user plugin

[leestwise]

...I installed under plugins directory the file user-managment.php and the folder user-managment which includes the file user-managment.php and the folder user-managment which includes the file ckeditor.php and the folder lang with english and italian as the only language.
...
Costas Lazarou
from Toronto Canada

You probably just mistyped; but, if you really did what your post literally says, your directory structure is

.........plugins[user-management[user-management...]],

which is one too many user-management directories.

...lee