Search notes:

ORA-29280: invalid directory object

The error ORA-29280: invalid directory object might be thrown if a directory name is specified in the wrong case (it typically should be uppercase).

create directory ext_dir as …;

begin
   utl_file.fremove (
      location => 'ext_dir',  -- Throws error if directory name is in lowercase
      filename => 'data.csv'
   );
end;
/

ORA-29280: invalid directory object

See also