I have located a possible problem that may have caused my server not being able to retrieve the return string:
Currently, the msxml3.dll error 'c00ce56e' is returned when calling the MSXML2.responseText property. Apparently this is a known issue with Java platform. From the support page from Microsoft.com, the error c00ce56e is generated by communicating with a Java Based application framework which has ISO8859_1 encoding string. For MSXML, it requires the alias to be ISO-8859-1.
The exact description of the error can be found at the Microsoft website: