You tried to execute an SQL statement that contains an invalid join. This error occurs when you try to create a join on a field that is not in one of the joined tables. The following example produces this error.
SELECT Authors.FirstName, Titles.ISBN
FROM Authors, Titles, AuthorTitles,
Authors INNER JOIN Titles ON Authors.ID = AuthorTitles.ISBN;
The error occurs because the join involves the Authors and Titles tables, but the joined fields are in the Authors and AuthorTitles tables.