The host variable data definition does not match the column type associated with it in the SQL statement. For example, you would get this error if you use a host variable defined as PIC X(n) with a column defined as SMALLINT.
Resolution:
Verify that the host variable definition corresponds appropriately to the column definition and make any changes to correct the error. Alternatively use the Host Compatibility Option DCLGEN tool to generate a copybook of the host variable for the SQL table in question.