I just want to say that I reinstalled the driver and the following are exists:
C:\Program Files (x86)\GHI Electronics\GHI Premium NETMF v4.2 SDK\Assemblies\GHI.Premium.USBHost.dll
C:\Program Files (x86)\GHI Electronics\GHI Premium NETMF v4.2 SDK\Assemblies\GHI.Premium.USBHost.xml
And I think it happens only with the usb module.
EDIT: Created a new project just to check and there was no problem adding the module, apparently only on my current project.