You can open the .tgd file in any regular text editor (such as Notepad or my personal favorite
PSPad [Windows]). Search in the file for path statements and make sure there are no special, unusual, or non-english characters, including cyrillic, accent marks, etc. Adjust the paths in the file and the actual file locations to remove any such characters. The easiest way to do this would be to copy the .tgd file and all supporting files (including image maps, objects, textures, etc.) to a special folder in your root directory, such as C:\TG2\
TG2 will be made more compatible with the full character set in the future.
- Oshyan