try  {
      String SqlNew = "INSERT INTO USERS" +
           "(USERS.ID_USR, USERS.LOGIN, USERS.PASS) " +
           "values " +
           "(12, '" + jTextField1.getText() + "', '" +
jPasswordField1.getText() + "')";
      database1.setConnection( new 
com.borland.dx.sql.dataset.ConnectionDescriptor("jdbc:interbase://localhost/
E:\\web\\SITE_BD.GDB", "sysdba", "masterkey", false,
"interbase.interclient.Driver"));
      Statement state = database1.getJdbcConnection().createStatement();
      jTextArea1.setText(SqlNew);
      state.executeQuery(SqlNew);
      database1.commit();
    }
     catch  (SQLException ioe) {
      jTextArea1.setText(jTextArea1.getText() + ioe.getMessage());
    }
  }

[interclient] Invalid operation to executeQuery on an update statement.
See API reference  for  exception
interbase.interclient.InvalidOperationException