qbasic.hlp (Topic list)
Important Notice
The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.
Duplicate definition
You are attempting to create a new element in your program
and have given it a name that is already being used.
 
For example:
  ■ A CONST statement uses the same name as an existing
    variable.
  ■ A new variable or procedure has the same name as an
    existing procedure.
 
Starting a variable name with the letters "FN" is another
way to generate this error, because FN is used exclusively
with DEF FN.