This refers to black frames that have been generated during the digitisation process, not black frames that are present in the physical filmstrip (for example, black frames cut into a film negative in place of a bad tear, a technique used to maintain sync between image and sound negatives).
Can it be fixed?
If the black frame in the file replaces an actual frame of the film, then no. The black frame can be removed, but the missing frame needs to be re-digitised, otherwise the file is not complete.
When the black frame is added in the file to the actual frames, then yes, it can be removed.