It's the dialer. Some of the dialers prevent us from using the phone codes.The newest vogue dialer will work with Sprint but that's all I know. Also make the carrier was installed properly.

I just re-read your post and have the following advise..

Just flash back to a stock verizion rom (make sure it's the correct one.) Of find the DCD carrier cabs over at xda-developers.com and install it.....I don't think it has anything to do with unlocking and everything to do with letting Sprint customs install. Good luck.