This message appears on the system console to indicate that the floppy driver fd(4) could not read the label on a diskette. Usually this is either because a new diskette has not yet been formatted, or a formatted diskette has become corrupted. This message often appears along with "read failed" and "bad format" messages after volcheck(1) is run.
If you are certain that the diskette contains no data, run fdformat -d to format the diskette in DOS format. (You can also format a diskette in UFS format if you like, although then it cannot be transported to most other systems.) When the diskette is formatted, you can write on it, if it was not corrupted beyond repair.