procedure closeDBFfile;

When you finish working with a DBF file you have to close it.

var
    dbf: TcdbfapiPlus;
begin
    dbf := TcdbfapiPlus.Create;
    if (dbf.openDBFFile('c:\tmp\example.dbf')) then
    begin
        // your code
        dbf.closeDBFFile;
    end;
    dbf := nil;
end;