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/RowSaveUtil.java
* @param currIndex
	 * @param exprID
	 * @param exprValue
	 * @throws DataException
	 */
	private int saveExprValue( Map valueMap ) throws DataException
	{
		ByteArrayOutputStream tempBaos = new ByteArrayOutputStream( );
		BufferedOutputStream tempBos = new BufferedOutputStream( tempBaos );
		DataOutputStream tempDos = new DataOutputStream( tempBos );
		try
		{
			IOUtil.writeInt( tempDos, valueMap.size( ) );
			Iterator it = valueMap.keySet( ).iterator( );
			while ( it.hasNext( ) )
			{
				Object key = it.next( );
				Object value = valueMap.get( key );
				IOUtil.writeObject( tempDos, value );
			}
			tempDos.flush( );
			tempBos.flush( );
			tempBaos.flush( );
			byte[] bytes = tempBaos.toByteArray( );
			int rowBytes = bytes.length;
			IOUtil.writeRawBytes( this.rowExprsDos, bytes );
			tempBaos = null;
			tempBos = null;
			tempDos = null;