Did you manually edit registry?
Here:
HKEY_CURRENT_USER\Software\JRiver\Media Center 20\TV Settings\Shared\
The value of "Default Channel Type Order" is empty. It is not supposed to be empty. It could be a bug for a new library.
Deleting "Default Channel Type Order" (delete it, not empty its value) should fix it for you. Once it is deleted, MC will use default.