That did it, thanks! They should maybe put a little readme or something in there to tell you to do that.
Generally what you should do when an addon isn't even showing up on the addons list is to go into the folder and see where the "AddonName.lua" file is and make sure that folder is the one directly under the "AddOns" folder.
For example "Interface\AddOns\WIM\WIM.lua"
"WIM.lua" is located in the "WIM" folder, so that folder should be directly under the "AddOns" folder. A ".lua" file is the core of an addon, the part that tells WoW what other files it needs to load in order to run the addon. WoW only looks 1 folder deep into the "AddOns" to find the initial ".lua" for an addon, therefore they can't be in a subfolder.
Anyways, it couldn't hurt to put a little "ReadMe" in there anyways.