using PPT 2003 - I am trying to link (not embed) to a png file. I have tried Insert, Picture, From File then chosen Link to File from the Insert button drop down, and have also tried Insert, Object, Create from File, selecting the Link to File checkbox.
With Insert, Picture, the graphic is placed on the slide but does not appear to create a link, since the Edit, Link option is not available (is grayed out).
With Insert, Object, I get a message that says "It isn't possible to create link to (path and filename)."

Can someone tell me what is causing this problem? thanks

It's because that Link option you are talking about means something else than you think... It means that there is a link (not hyperlink) to the linked file... So when you change the image file it will be updated in the ppt as well...