As a fix/workaround – replace the following code in the ProcessMeasureRequest function in Measure.ascx.cs in the WMA Replace coll.Add(new CallbackResult("","","invoke","measureComplete", new object[] { response, m_id, area, perimeter, segmentDistance, totalDistance })); return coll.ToString(); with coll.Add(new CallbackResult("","","invoke","measureComplete", new object[] { response, m_id, area, string.Format("{0}", perimeter), string.Format("{0}", segmentDistance), string.Format("{0}", totalDistance) })); return coll.ToString(); If you could put this information inside the CR, that would help the developer who fixes it eventually and also a possible workaround for SP1.<a href="http://frenchfrie/french_internet/Default.aspx" target="_blank">http://frenchfrie/french_internet/Default.aspx</a>