Even when you know how to install it

For information:
- Instead of launching the autorun, run setup.exe directly from the DVD (this avoids having to register JustForGames).
- Start the first time the "normal" version (= non Venice) of the game, it should be updated.
- Start the extension this time, the game should again be updated.
- If you do not have a net connection, patches are recoverable forum UBI. (Search "[Anno 1404] Patch 1.3 and 2.1 available" on a search engine)

After you apply patches, you should not need the CD key.

Edit: Thanks to delete my amazon have yet useful link ...