Internal problem on XmlDocument.Load( )

[Whugster]

I have this really frustrating problem when calling XmlDocument.Load(string
filename). Whenever I call this method in a web application in my Windows XP
development PC, I get the following error:

Specified argument was out of the range of valid values. Parameter name: The
specified value must be greater than 0.

Here's the stack trace:
-------------------------
[ArgumentOutOfRangeException: Specified argument was out of the range of
valid values.
Parameter name: The specified value must be greater than 0.]
System.Net.ServicePoint.set_ConnectionLimit(Int32 value) +60
System.Xml.XmlDownloadManager.GetNonFileStream(Uri uri, ICredentials
credentials) +282
System.Xml.XmlDownloadManager.GetStream(Uri uri, ICredentials
credentials) +94
System.Xml.XmlUrlResolver.GetEntity(Uri absoluteUri, String role, Type
ofObjectToReturn) +55
System.Xml.XmlTextReader.CreateScanner() +384
System.Xml.XmlTextReader.Init() +23
System.Xml.XmlTextReader.Read() +530
System.Xml.XmlValidatingReader.ReadWithCollectText Token() +146
System.Xml.XmlValidatingReader.Read() +26
System.Xml.XmlLoader.Load(XmlDocument doc, XmlReader reader, Boolean
preserveWhitespace) +80
System.Xml.XmlDocument.Load(XmlReader reader) +72
System.Xml.XmlDocument.Load(String filename) +78
..[my functions in here]...
-----------------------

The culprit seems to be in the System.Net.ServicePoint.ConnectionLimit
property, but this property is set inside a method called GetNonFileStream
and I see some credentials stuff going on in there. Maybe permission issue?
This error never happens in production Win2003 machines and in other WinXP
PCs.