Please keep in mind that you also have to install the newest Warband patch, before playing NW. You might experience crashes without updating Warband.
Besides that, some Servers might have the wrong/old server files, but changed their version number to 1103 to run. If you did that with your server, please use this simple fix to prevent crashes and bugs:
1.) Copy your Client NW folder, delete the sound, music and texture folder.
2.) Copy the remaining folders and files, and paste them into the Dedicated Server File folder.
3.) Click on "Replace All", setup your Server as usual and everything should work without problems.