We received many messages and read comments (in the french site) about troubles when downloading Manga Sudio Debut if you bought Intuos Manga (or previous tablet, Bamboo Manga – I don’t know if this model was sold in USA). Now Wacom gave an answer in the Wacom forum. Now you can’t download the soft >  « This software is currently not available. Please retry in a couple of days. » (in french > « Ce logiciel n’est pas disponible actuellement. S’il vous plaît réessayer dans quelques jours. » )
In fact, since one month there are many troubles ( we have feedbacks from WacometmaPomme readers since one month). Now it’s clear.
If you want a free software to draw Manga (or Comics), you can download :
– PC > Paint Tool Sai > http://detstwo.com/sai/index
– MAC > FireAlpaca  > http://firealpaca.com/

I learned that Manga Studio is edited in english with another name  ( forum deviantart ) : Clip Studio Paint.. If you know the right story why, you can write a comment.