Bug 153853 [Regression]The bound column names must be unique within the entire table.
Regression case Regression_136421(under org.eclipse.birt.report.tests.model) failed. Expected result: Model will avoid adding a duplicate bound column name within a table.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ModuleHandle.java
return;
		module.prepareToSave( );
		String resolvedFileName = URIUtil.getLocalPath( fileName );
		if ( resolvedFileName != null )
			fileName = resolvedFileName;
		module.getWriter( ).write( new File( fileName ) );
		module.onSave( );
	}
	/**
	 * Saves the design to the file name provided. The file name is saved in the
	 * design, and subsequent calls to <code>save( )</code> will save to this
	 * new name.
	 * 
	 * @param newName
	 *            the new file name
	 * @throws IOException
	 *             if the file cannot be saved
	 * 
	 * @see #save()
	 */
	public void saveAs( String newName ) throws IOException
	{
		setFileName( newName );
		save( );
	}
	/**
	 * Writes the report design to the given output stream. The caller must call
	 * <code>onSave</code> if the save succeeds.
	 * 
	 * @param out