My guess is that the POST data isn't correct when doing it with LabVIEW. Using Wireshark, or a similar utility you'd be able to compare the POST request between the two. If you can get the actual POST command that's required, then you can bypass the web browser control and use the TCP functions directly to send the POST command and then use TCP Read to read the response, which will be the HTML page, which you can parse using string functions.
