Bug 135790 ClassCastException in RowData.
ClassCastException is thrown in RowData line 81(IBaseExpression expr = ( IBaseExpression ) valueExpressions.get( index - 1 );).
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/parser/EngineIRVisitor.java
int size = parameters.getCount( );
		for ( int n = 0; n < size; n++ )
		{
			apply( parameters.get( n ) );
			if ( currentElement != null )
			{
				paramGroup.addParameter( (IParameterDefnBase) currentElement );
			}
		}
		currentElement = paramGroup;
	}
	public void visitCascadingParameterGroup(
			CascadingParameterGroupHandle handle )
	{
		CascadingParameterGroupDefn paramGroup = new CascadingParameterGroupDefn( );
		paramGroup.setHandle( handle );
		paramGroup
				.setParameterType( IParameterDefnBase.CASCADING_PARAMETER_GROUP );
		paramGroup.setName( handle.getName( ) );
		paramGroup.setDisplayName( handle.getDisplayName( ) );
		paramGroup.setDisplayNameKey( handle.getDisplayNameKey( ) );
		paramGroup.setHelpText( handle.getHelpText( ) );
		paramGroup.setHelpTextKey( handle.getHelpTextKey( ) );
		DataSetHandle dset = handle.getDataSet( );
		if ( dset != null )
		{
			paramGroup.setDataSet( dset.getName( ) );
		}
		SlotHandle parameters = handle.getParameters( );