Bug 135465 [smoke]An error occurred when new a casading Parameter
Description: An error occurred when new a casading Parameter Step to reproduce: 1.new a sample db data source and data set 2.New a cascading parameter group, named "gp1", 3.select the data set, then create two cascading parameters, one is row["customernumber"], named p1; the other is row["customername"] Actual result; error message occurred repeatly
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/CascadingParametersDialog.java
try
				{
					( (ScalarParameterHandle) actualElement ).setValueExpr( DEUtil.getColumnExpression( (String) value ) );
				}
				catch ( SemanticException e )
				{
					ExceptionHandler.handle( e );
				}
			}
			else if ( COLUMN_DISPLAY_TEXT.equals( property ) )
			{
				try
				{
					( (ScalarParameterHandle) actualElement ).setLabelExpr( DEUtil.getColumnExpression( (String) value ) );
				}
				catch ( SemanticException e )
				{
					ExceptionHandler.handle( e );
				}
			}
			if ( actualElement == newParameter )
			{
				if ( newParameter.getValueExpr( ) != null
						&& newParameter.getValueExpr( ).trim( ).length( ) > 0 )
				{
					try
					{
						inputParameterGroup.getParameters( ).add( newParameter );
					}
					catch ( SemanticException e )