"Error: The mod 'Unique Landscapes Compilation 1.5.4.omod'

[_Vagrant_]

EDIT: Never mind. I figured it out. I'm still not sure quite what happened though.

 

I recently installed Oblivion on my new Windows 7 PC. I patched it. It's all working fine on its own.

 

I downloaded the Oblivion mod manager and set it up.

Then I downloaded the Natural Environments mod, and installed it how the readme told me to. (without the mod manager)

Finally I downloaded the Unique Landscapes Compilation OMOD thing. I extracted the omod file from the .rar and opened it. (from my downloads folder, if that makes a difference?)

And then this message came up:

Error

The mod 'Unique Landscapes Compilation 1.5.4.omod' appears to already be installed.

It's just not letting me add the OMOD to the manager.

(I also had to go to the mod manager exe's properties and set it to run as administrator and let it move files from the virtual store?)

 

I've been far away from the modding scene and don't know what in the hell I am doing. So, yeah. Any ideas how to fix this or what I've done wrong? Help'd be appreciated.