Most of these errors are caused because the symlink creation process that occurs on start up fails. The most common reason is the drive LaunchBox is on is not NFTS but there are other causes. You should be able to turn on debug logging and then try to start up into the theme to get the error, then just close LaunchBox (or Big Box) and look in the log to see whether that process failed or not, and any information as to why it failed. Another easy way to tell if this process happened correctly is to open LaunchBox, then go to the \\LaunchBox\Core\ folder and look for a LBThemes or Themes folder. If there is an actual folder there (and not a shortcut) then the symlink process is failing on your machine.