Here's what you should do: Go to your Addon folder. Find the folder of the addon you're trying to install. Rename it to addons.old. Rename the addon folder to addons. Then, install the addon. If you're using Tukui, you can also just download the addon again. Hope this helped!
We are happy to announce that the Gates of Worlds update will arrive on October 14, 2013. This update is a major upgrade with many new features and improvements.
The 13.0 update brings a lot of new exciting content to the game – new quests, a new faction, a new PvP map, reworked PvP combat and much more. Collector's Editions are available for a pre-order right now, in the official Allods Online store.