JJ,
By choice or force of habit, the snare hits have been placed on the treble clef A space. Changing them is easy. Go back to to Layout menu (ScoreManager>Notation>Percussion>Select), click on the map in question (in this case the SnareLine Manual), then click Edit (lower left corner of the window) and you should see all of the sound mappings (noteheads and staff placement). You can change either of these using the windows on the right side of the Edit Window. Let me know if you have any other questions.