As the error says, "ntlm_auth was not found or is outdated..."
"Usually, you can find it in the winbind package of your distribution."
* Winbind is usually bundled with samba, e.g. samba-winbind. Use your distro's package manager to install it.
* Check the AppDB for a workaround regarding the issue with winhttp.dll being outdated.
http://appdb.winehq.org/objectManager.php?sClass=application&iId=6807 says the noCD crack patch breaks the updater, so get rid of that, if present.
* The AppDB is outdated. There is no entery for Assassin's Creed 2. Go ahead and add one and set yourself up as a maintainer.
* File a bug report
Edit: * I forgot to add "winetricks gecko" to the list of things to try.
