xfa.sourceSet.Dataconnection is undefined

Hi,

I have a Livecycle designer 8 form and used dynamic dropdownlist with ODBC connection. After applying usage rights to the form using acrobat professional when i open with reader my first dropdown is showing records but the dependent dropdown in blank. If i open the same form with acrobat it is working (The second dropdown is populating records according to first dropdown).

when i debug in adobe reader it gives "xfa.sourceSet.Dataconnection is undefined".

My Javascript code for second dropdown preOpen Event :

-------------------------------------------------

this.clearItems();

xfa.sourceSet.City.first();   Error in this line.

while(!xfa.sourceSet.City.isEOF())

{

if (xfa.resolveNode("$record.City.state_DCode").value ==xfa.resolveNode("Row1[0].presSTATE").rawValue)

{
  this.addItem(xfa.resolveNode("$record.City.Dist_Name").value,

               xfa.resolveNode("$record.City.Dist_Code").value);

}

xfa.sourceSet.City.next();

}