After watching your latest Videos on DNN5 Skinning, I created a package for my site. (Very good tutorial!)

However, when I tried to delete this skin from the Admin/Skins menu, I got this message:

This skin is part of a Skin Package. Use the Uninstall Package option in the list of Skins in the main Grid.


What/where is the "main Grid"?  Is this Host/Extensions?

My site is generating an error on the Host/Extensions page. 
When I go to Host/Extensions - I get the error below. 
(everything else is working fine on the site)

Server Error in '/' Application.

---

Object reference not set to an instance of an object.

full error message in attachment.

Is there an easy way to fix this problem?
If not - is there a manual procedure to uninstall the skin package?

Simply delete the directory that holds the skin.

Yes, that's true.

But, if you are trying to get rid of a skin that is misbehaving, deleting the directory works just fine. 

I'm having a similar problem. I originally loaded the skin pagkage under the Admin Extensions (dnn 5.5.1) then decided I wanted it at the Host level. I tried to delete and got the same error. So I deleted the folders in the portals/0/skins and portals/0/container folders. Now when I try to install them under the Host/Extensions I get a "This package is already installed" and I can't go any further. Any ideas why?

You could try renaming the skin and installing it with a new name.  I think that all you need to do is rename the ZIP file.

You then might be able to "delete" the existing file.