Both servers are Windows 2003.  I have several other charts (bar, pie etc) working perfectly on the web server.

I'm not sure what I can be doing wrong - any help much appreciated.

My javascript:

   <script language="JavaScript"> 
      var chart1 = new FusionCharts("../Charts/Gantt.swf", "chart1Id", "1000", "600", "1", "1"); 
      chart1.setDataURL("bookings%5Fgantt%2Easp%3Fyear%3D2008%26limit%3D1");
      chart1.render("chart1div");
   </script>

My XML:

<chart dateFormat='dd/mm/yyyy' ganttPaneDuration='1' ganttPaneDurationUnit='m' palette='2' showShadow='0'><categories><category start="01/01/2008" end="31/12/2008" name="Bookings grid view" /> </categories><categories><category start="01/01/2008" end="31/01/2008" name="Jan" /><category start="01/02/2008" end="29/02/2008" name="Feb" /><category start="01/03/2008" end="31/03/2008" name="Mar" /><category start="01/04/2008" end="30/04/2008" name="Apr" /><category start="01/05/2008" end="31/05/2008" name="May" /><category start="01/06/2008" end="30/06/2008" name="Jun" /><category start="01/07/2008" end="31/07/2008" name="Jul" /><category start="01/08/2008" end="31/08/2008" name="Aug" /><category start="01/09/2008" end="30/09/2008" name="Sep" /><category start="01/10/2008" end="31/10/2008" name="Oct" /><category start="01/11/2008" end="30/11/2008" name="Nov" /><category start="01/12/2008" end="31/12/2008" name="Dec" />
</categories><processes align="left"><process Name="97 - Orroland Lodge" id="97" /></processes><tasks><task name="Christine Prunty" processId="97" start="04/01/2008" end="07/01/2008" taskId="B" borderColor="D85958" color="D85958" link="bookings_detail.asp?bookingID=17220" /><task name="Sharon Ward Giles" processId="97" start="05/01/2008" end="19/01/2008" taskId="B" borderColor="303B7D" color="303B7D" link="bookings_detail.asp?bookingID=16809" /><task name="Building and maintenance" processId="97" start="07/01/2008" end="26/01/2008" taskId="B" borderColor="367D5F" color="367D5F" link="bookings_detail.asp?bookingID=20723" /></tasks></chart>

The debug information:

INFO: Chart registered with external script. DOM Id of chart is chart1Id
INFO: XML Data provided using dataURL method.
dataURL provided: bookings_gantt.asp?year=2008&limit=1
dataURL invoked: bookings_gantt.asp?year=2008&limit=1
ERROR: An error occurred while loading data. Please check your dataURL, by clicking on the "dataURL invoked" link above, to see if it's returing valid XML data. Common causes for error are: 
No URL Encoding provided for querystrings in dataURL. If your dataURL contains querystrings as parameters, you'll need to URL Encode the same. e.g., Data.asp?id=101&subId=242 should be Data%2Easp%3Fid%3D101%26subId%3D242
Different sub-domain of chart .swf and dataURL. Both need to be same owing to sandbox security.
Network error