Bug 156166 Error occour when previewing attached report in web viewer.
Decription:Error occour when previewing attached report in web viewer. Steps to reproduce: 1.run attached reports in web viewer. Expeceted results: preview properly Actual results: Error occour when previewing the reports in web viewer while it works properly in html and PDF
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/document/util/ExprDataReader1.java
* @see org.eclipse.birt.data.engine.impl.document.IExprResultReader#getRowValue()
	 */
	public Map getRowValue( ) throws DataException
	{
		try
		{
			if ( currReadIndex < currRowIndex + 1 )
			{
				this.skipTo( currRowIndex );
				this.exprValueMap = this.getValueMap( );
			}
			currReadIndex = currRowIndex + 1;
		}
		catch ( IOException e )
		{
			throw new DataException( ResourceConstants.RD_LOAD_ERROR,
					e,
					"Result Data" );
		}
		return exprValueMap;
	}
	/**
	 * @param absoluteRowIndex
	 * @throws IOException
	 * @throws DataException
	 */
	private void skipTo( int absoluteRowIndex ) throws IOException, DataException
	{
		if ( currReadIndex == absoluteRowIndex )
			return;