non-exclusive problem!(help)

Hi, Folks: I meet some problem that I always get the exception "informix.api.DBServerException: XIX000:-106:ISAM error: non-exclusive access." when I try to drop the table. I believe what I do is really simple, but I really can't find where is my problem at all. Does anyone know where the problem is? The problem is described briefly as follows: ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Everthing work fine except that if I select data from table and then drop it. The error message "non-exclusive" will apear, and the table still exist.... And so I guess the problem comes from select part,but I have no idea about it..... //IDE: VisualCafe 4 //LANGUAGE: Java import informix.api.*; import informix.api.remote.rmi.*; //connecton method import informix.api.*; import informix.api.remote.rmi.*; Connection conn; Query query; Credentials cred; try{ cred = new RMICredentials(appServer, db, user, sys, passwd); conn = cred.connection(); query = conn.query(); }catch (Exception exec){;} try{ conn.open(); }catch (Exception exec){;} // create table String Create_qry = new String("CREATE TABLE e (img_id integer);"); try{ if (!query.execForStatus(Create_qry)) ; }catch (DBException dbexc){;} // insert data into table String insert_qry = "insert into e (img_id) values(9);"; try{ if (query.execForStatus(insert_qry)==false) ; }catch (DBException dbexc){;} <!-- the problem will appear everytime when I execute the code below --> // retireve data from table Row row; String select_qry = new String("select img_id from e;"); try{ if (!query.execForIteration(select_qry)) System.out.println("Could not excute select_from_temp_qry!"); while ((row = query.nextRow()) != null) { ; } } catch (DBException dbexc){;} <!-- end --> // delete data in table String Delete_qry = new String("delete from e where img_id<>0;"); try{ if (!query.execForStatus(Delete_qry)) ; }catch (DBException dbexc){;} // drop table String Drop_qry = new String("DROP TABLE e;"); try{ if (!query.execForStatus(Drop_qry)) ; }catch (DBException dbexc){;} thanks a lot! Joe