Bug 207897 [Automation][Regression]A DataException is thrown out when preview reportdesign
Description: A DataException is thrown out when preview reportdesign Test Date: 20071030 Test Build: BIRT2.2.2 v20071029 Step to reproduce: 1. Use the reportdesign attached 2. Preview it Expect result: Report can be previewed without any exception. Actual result: A DataException is thrown out.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/executor/ExecutionContext.java
* Evaluate a BIRT expression
	 * 
	 * @param expr
	 *            the expression to be evaluated
	 * @param name
	 *            the file name
	 * @param lineNo
	 *            the line number
	 * 
	 * @return the result if no error exists, otherwise null.
	 */
	public Object evaluate( String expr, String name, int lineNo )
	{
		if ( expr != null )
		{
			try
			{
				return scriptContext.eval( expr, name, lineNo );
			}
			catch ( Throwable e )
			{
				log.log( Level.SEVERE, e.getMessage( ), e );
				addException( new EngineException(
						MessageConstants.SCRIPT_EVALUATION_ERROR, expr, e ) ); 
			}
		}
		return null;
	}	
	/**
	 * evaluate conditional expression. A conditional expression can have an