Error Building Admin Menus on 2.2.1 installation

[Dekle]

I get this error trying to install the package on a 2.5.6 site:

Another menu item with the same parent has this alias
Error building Admin Menus

I have removed every reference, every module, every plugin, every component, every menu item having anything to do with xmap and still can't get the package to install.

After installing and getting the error, the component does not appear in Components but the plugins and com items are shown. I have enabled the plugins needed for the component and the features on the site.

Is there a solution for this?

Thanks for any help.