Fresh post image upload

Hi, I’m trying to use Fresh post, with custom write panels.
I created custom fields and everything looks ok, except I can’t seem to upload an image using the custom imge field. When I upload I don’t get an error, but if I click “view current” in the write preview, I get a 404, and the file doesn’t get uploaded. I tried creating a “Files” dir within /plugins/fresh-page/, which I chmoded 666, to no luck. Any idea? TIA.