[Slick]

Are you using Matrix's Mod Launcher (which is installed with the TDM Modpack)? If so, sometimes it gets a little screwey when it comes to loading a saved game. Make sure your player number and password are correct. If you are playing single player and didn't put in a password, then your player number is 1 (usually) and your password will be the default, just a blank space " ".

edit: that would be a single blank space, just to be clear. Sometimes the mod launcher gets confused on the game passwords when you delete some saved games.