I'm not sure, but I seem to remember a thread on one of the old boards that suggested that, depending on which version of the game you installed origianlly, you might get the standard portraits without the software having actually created the separate folder that the cc looks for. Check your NWN folder to make sure that there actually is a portrait folder in it.
If you find that one is not there, simply create it. Then download the standard portrait pack from the vault and install the portraits to the folder you created. That will give the CC access.
This may not be your problem, but I know the problem exists sometimes, so it is worth checking.