A possibility:
In your point settings, on the Insert tab, do you have "Use Current Point Label Style When Inserting Points" set?
If yes, then check the "active deskeys only" point style. In your Label menu, select "Edit Label Styles", and select the style named "active deskeys only". Is the box marked "Turn Off Marker Text" checked? If so, and you haven't configured any of the other options on this tab, then this is your problem.
LDD actually has TWO labels associated with each point. One is a minimal label, called a marker, which can contain only a point symbol (which you must select from a limited selection), a deskey symbol (which can be any block), a point number, a description, and an elevation. This marker is what people use most often, and what they generally mean when they say "point label". However, AutoCAD also has a point label, which is fully customizable, and lets you label points with anything, including data you have referenced in from an external database. But you have to set up the label style, first; that's what all the settings on this page are for. An individual point can be labeled with just the point, just the marker, or both.