some questions that might help you
1 do you have a playerRACE.entity file for the new race?
2 have you added all the new entity files to the entity.manifest?
3 did you add any player themes?
4 did you add the new playerthemes to the PlayerThemes.manifest?
5 did you add any player pictures?
6 did you add the PlayerPictures to the PlayerPictures.manifest?
hope these questions help
harpo