Well, i have noticed that many people do something that make the 7zip to not actually unzip or overwrite the files.
The way to do it in an empty directory is:
1. Get OTTD and unzip that into the directory.
2. Get the graphicsfiles required by OTTD and place them in the data subdirectory.
3. Get copy&paste and use 7zip to extract and overwrite the files it need to in the directory you unzipped the OTTD game into.
The general idea is to completly replace A LOT of the files with new ones, including the languagefiles.
I'd suggest that you check that the filedate and filesize of the .exe have changed.
Actually i had the same problem myself for very long before i finally undestood that i had not done what i thought i did.
And yes, copy&paste is really a useful tool
