Strange issue in embedded sql

I have a program which accepts the Sql statements user enters and these
statements are passed onto a sqlrpgle program which declare a scroll cursor
and prepares the sql from the string which holds input parameter. It then
issues a fetch first statement into a field which will hold the query
reasult. I am checking sql code to determine whether the entered query is
valid or not. I close the cursors after this. If first time i entered a
valid sql i get the result..for second time if some irrelevant data is
entered still the fetch statement returns previous sql's output and sqlcod
also is zero as if i entered correct sql. Pls help me to figure out the
problem here....