Xmlhttp Object Causing System & Runtime Error 1072896658 (c00ce56e)

I have just signed up to the forums as I am having a very specific problem. I have looked on google and used the search feature (on several forums!) and found very limited information that is useful to me. I am having trouble with a very simple few lines of code in a macro. The code looks like this:

Function startmarketIDs()
Dim targeturl, writerow, readrow, textmass, xmlHTTP
targeturl = "http://lite.betfair.com/ Events.do?s=00010913z"
Set xmlHTTP = CreateObject("Microsoft.xmlHTTP")
xmlHTTP.Open "GET", targeturl, False
xmlHTTP.send
MsgBox xmlHTTP.StatusText
textmass = xmlHTTP.responsetext
MsgBox textmass
End Function

My problem occurs at the line "textmass = xmlHTTP.responsetext". The responsetext command is obviously causing problems because if I remove it, the code executes without error and the "xmlHTTP.statustext" says "OK". With the responsetext command left in, the code generates the following error: Run-time error '-1072896658 (c00ce56e)': System Error: -1072896658. If I change the targeturl to www.betfair.com, the code executes fine and I get a message box (as desired) with the source code of the website displayed. Without meaning to sound like Im answering my own question (!!), perhaps there is something about the url or the way in which I am using the xmlHTTP object that is causing the issue, I wondered if someone would mind inspecting my code and perhaps pointing me in the right direction?