Bug 136553 [regression]Preview error when set invalid group interval.
Description: Preview error when set invalid group interval. Steps to reproduce: 1. Insert a table 2. Add a group on number column, set interval to Year,1 3. Preview 4. Edit group on string column set interval to Prefix,1 5. Preview Expected result: Error msg about invalid group interval. Actual result: Error happened while running the report
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/data/dte/DataPresentationEngine.java
if ( queryResults == null )
			{
				resultSetID = getResultID( null, -1, queryID );
			}
			else
			{
				String pRsetId = queryResults.getID( );
				long rowid = parentResult.getCurrentPosition( );
				resultSetID = getResultID( pRsetId, rowid, queryID );
			}
			if ( resultSetID == null )
			{
				logger.log( Level.SEVERE, "Can't load the report query" );
				return null;
			}
			queryResults = dteEngine.getQueryResults( resultSetID );
			DteResultSet resultSet = new DteResultSet( queryResults, this,
					context );
			rsets.addFirst( resultSet );
			return resultSet;
		}
		catch ( BirtException be )
		{
			logger.log( Level.SEVERE, be.getMessage( ) );
			context.addException( be );
			return null;
		}
	}
}