Hi Luca,
Were you able to open the MRI volume in the BrainSuite? What kind of data format are you using?
Also there is a test data available on the BrainSuite website. Can you try and see if you can open that data?
Here is a link to the test data.
http://brainsuite.org/WebTutorialData/BrainSuiteTutorialCSE_Feb15.zip
Anand