Bug 179661 NPE throws out when preview the attached report [1102]
Description: NPE throws out when preview the attached report [1102] Build number: 2.2.0.v20070328-0630 Steps to reproduce: 1, Using attached report design file 2, Preview Expected result: Previewed successfully Actual result: NPE throws out when preview Error log:
data/org.eclipse.birt.report.data.adapter/src/org/eclipse/birt/report/data/adapter/impl/DataRequestSessionImpl.java
* 
	 * @see org.eclipse.birt.report.data.adapter.api.DataRequestSession#refreshMetaData(org.eclipse.birt.report.model.api.DataSetHandle,
	 *      boolean)
	 */
	public IResultMetaData refreshMetaData( DataSetHandle dataSetHandle,
			boolean holdEvent ) throws BirtException
	{
		return new DataSetMetaDataHelper( this.dataEngine,
				this.modelAdaptor,
				this.sessionContext ).refreshMetaData( dataSetHandle, holdEvent );
	}
	/*
	 * @see org.eclipse.birt.report.data.adaptor.api.DataRequestSession#executeQuery(org.eclipse.birt.data.engine.api.IQueryDefinition,
	 *      java.util.Iterator, java.util.Iterator, java.util.Iterator)
	 */
	public IQueryResults executeQuery( QueryDefinition queryDefn,
			Iterator paramBindingIt, Iterator filterIt, Iterator bindingIt )
			throws BirtException
	{
		return new QueryExecutionHelper( this.dataEngine,
				this.modelAdaptor,
				this.sessionContext ).executeQuery( queryDefn,
				paramBindingIt,
				filterIt,
				bindingIt );
	}
	/*
	 * @see org.eclipse.birt.report.data.adaptor.impl.IDataRequestSession#getQueryResults(java.lang.String)
	 */
	public IQueryResults getQueryResults( String queryResultID )