Hi Enrico,
My name is Andy and I work with the ArcGIS for Maritime: Bathymetry team. Can you provide a little more information regarding your 10.1 setup, like do you have the latest Service Pack and QFE installed (10.1 SP1 QFE3)? Also, which BAG datasets did you download from the NOAA site? This will help us provide an answer to the issue you are seeing.
Thank you
Andy