I have already tested with single table schema.it was working perfect.
I think it's not a issue of Oracle Data provider because i have previewed all data in Schema designer, all data was fetched from database without any error.
One more thing which is very much intersting to me that it works fine if i programatically Instanciate new dataset and fill with library at run time . I'm really unable to get why it's not working at design time.
i have tested at three machine there were same problem in three machine.