win32com.client.Dispatch - understanding error messages

[mirandacascade at yahoo.com]

O/S : Win2K
vsn of Python: 2.4

Hoping to find information that provide information about error
messages being encountered.

Pythonwin session:

>>> import win32com.client
>>> blah = win32com.client.Dispatch('MSXML2.XMLHTTP')
>>> blah.open("POST", "12.5.81.49/crg_cbsil_vtest_52/crg.aspx", 0)
Traceback (most recent call last):
  File "<interactive input>", line 1, in ?
  File "<COMObject MSXML2.XMLHTTP>", line 4, in open
com_error: (-2147352567, 'Exception occurred.', (0, None, None, None,
0, -2147467259), None)

I tried various combinations in Google involving
"win32com.client.Dispatch", "MSXML2", "XMLHTTP" and the 2 different
error codes: -2147352567 and -2147467259.  So far, I haven't been able
to locate anything that has helped me zero in on the error.

The fact that no error was issued after the blah = ... statement plus
the fact that as soon as I typed the '(' character after blah.open,
that the arguments for the open method were displayed; those two things
make me think that the COM object is installed/registered on the
workstation.  Is that a reasonable conclusion?

I observed that there are a few other similarly named objects/methods,
so I tried them as well.  The error messages reference some different
dll's, but those error message seemed as inscrutable as the first set
of error messages above.

>>> blah = win32com.client.Dispatch('MSXML2.XMLHTTP.4.0')
>>> blah.open("POST", "12.5.81.49/crg_cbsil_vtest_52/crg.aspx", 0)
Traceback (most recent call last):
  File "<interactive input>", line 1, in ?
  File "<COMObject MSXML2.XMLHTTP.4.0>", line 4, in open
com_error: (-2147352567, 'Exception occurred.', (0, 'msxml4.dll',
'System error: -2147012890.\r\n', None, 0, -2147012890), None)

and

>>> blah = win32com.client.Dispatch('MSXML2.ServerXMLHTTP')
>>> blah.open("POST", "12.5.81.49/crg_cbsil_vtest_52/crg.aspx", 0)
Traceback (most recent call last):
  File "<interactive input>", line 1, in ?
  File "<COMObject MSXML2.ServerXMLHTTP>", line 4, in open
com_error: (-2147352567, 'Exception occurred.', (0, 'msxml3.dll',
'Unspecified error\r\n', None, 0, -2147467259), None)

Also tried varying the 3rd argument...instead of using 0 to represent
False, I tried:

>>> False
False
>>> blah = win32com.client.Dispatch('MSXML2.XMLHTTP')
>>> blah.open("POST", "12.5.81.49/crg_cbsil_vtest_52/crg.aspx", False)
Traceback (most recent call last):
  File "<interactive input>", line 1, in ?
  File "<COMObject MSXML2.XMLHTTP>", line 4, in open
com_error: (-2147352567, 'Exception occurred.', (0, None, None, None,
0, -2147467259), None)

So, if possible, it would be nice to know two different types of
things:
1) what steps to take to correct these errors
2) where one can locate information about these types of errors