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/ExprDataReader2.java
int exprCount = IOUtil.readInt( rowExprsIs );
			this.exprKeys = new ArrayList();
			this.rowExprsDis = new DataInputStream( rowExprsIs );
			for( int i = 0; i < exprCount; i++ )
			{
				this.exprKeys.add( IOUtil.readString( this.rowExprsDis ) );
			}
			this.metaOffset = IOUtil.INT_LENGTH
					+ IOUtil.readInt( this.rowExprsDis ) + IOUtil.INT_LENGTH;
			
		}
		catch ( IOException e )
		{
			throw new DataException( ResourceConstants.RD_LOAD_ERROR,
					e,
					"Result Data" );
		}
		
		this.rowExprsIs = rowExprsIs;
		this.rowLenIs = rowLenIs;
		
		this.currRowIndex = -1;
		this.lastRowIndex = -1;
		this.currRowLenReadIndex = -1;
		
		this.rowIDMap = new HashMap();
	}
	
	/**
	 * @param rowExprsIs