502 error using wininet

Hi, I am getting a 502, bad gateway error when try posting on to a
ashx page from my VC application. If i open the same URL in IE it
works fine.

I am doing a HTTPS connection to server and IE opens the same from
that website.

Other part of my code does InternetOpenUrl and able to read from the
site, but when i do the post on the same serve with my custom headers
it is giving this problem.
Can some one point me to things i should look for to solve this
problem?

thanks
-g:P