Like salem said, you would be better off with a decent compiler such as gcc. If its not a problem with your compiler, then I'd guess you are not linking the library properly. Its been a while, but I had a play around with libpng once I dumped the code here on my site. It should work assuming its linked and compiled correctly.
No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.