I am using an MSXML.HTTPRequest object in a VB macro (excel) to communicate with an HTTP server. The problem is that it throws the following error intermittentl
Use MSXML v6.0, MSXML v3.0 is no longer distributed with Office or Windows. v6.0 is only distributed with Windows 7. But office 2010+ no longer comes with any version of MSXML any more. This explains the reasons for your issue.
It's also described in Wikipedia: http://en.wikipedia.org/wiki/MSXML