"Flying Mod Beta - Flying Mod v09 can't be added"

[Kroekr]

Possible problems:

 

Perhaps Revo did not remove the files from your appdata folder when you uninstalled. It is usually best to use the uninstall from the program itself if available.

During your re-installs, are you being careful with the install directories, making sure they are on the same drive and not in the program files directory?

It sounds to me that you have a partial or corrupted file of the flying mod listed in your \Nexus Mod Manager\Skyrim\Mods directory. I had this problem before and until I went through the NMM\Skyrim folder and manually deleted every reference to the mod, I was unable to get it to show because the old data was blocking the new install somehow.