If you used ChocolateBox with a previous installation of Fable that was uninstalled, then tried to use ChocolateBox with a new installation of Fable, you will get this error because the name that ChocolateBox tries to rename the FinalAlbion.wad to is already taken. The most appropriate action to take is to navigate to the data\Levels folder in your Fable install directory and delete the _FinalAlbion.wad (prefixed with an underscore (_)) and the FinalAlbion directory, leaving only the new FinalAlbion.wad file. This will allow CBox to set up the environment. This also removes any previous level edits, but seeing as how this is a new installation of Fable, this is most appropriate. Be advised that you may need to delete your saves and start a new profile.

If ChocolateBox cannot find the levs/tngs or the FinalAlbion.wad file, you will get this error.

If you manually dumped the FinalAlbion.wad using FreeRoam, then renamed the FinalAlbion.wad like you're supposed to, it is likely that you dumped the files into the wrong place. In the data\Levels directory of your Fable install directory, you might find yet another Levels directory (data\Levels\Levels). Right-click the Levels directory inside of the Levels directory, select Cut. Go to the data directory, right-click|Paste. Confirm the overwrite. You're done.

If you moved/deleted the FinalAlbion.wad without having dumped the files, you'll need to get another copy off of the discs.

If you have an FE-compiled FinalAlbion.wad (from using a mod that edits the FinalAlbion.wad, as could be determined by whether or not it makes an edit to a level), it is possible that ChocolateBox will be unable to extract the files. This is because when FE recompiles the FinalAlbion.wad, it "breaks" it. I haven't figured out exactly why this happens, because as far as I can tell all that happens is some padding between files gets removed, but anyway, moving on. You'll need to get a fresh copy off of your discs.

If you can think of anything else that you may have done that could cause a problem, tell us. If you were following some guide, tell us which one and provide a link.