Folderblog error….

I tried installing photoblog this morning, but i get this error whenever i try to create thumbs, but the folders are chmod to 777.
error:
Warning: imagejpeg(): Unable to open ‘gallery/thumbs/TheGirls3.jpg’ for writing in /home/ftpusers/r3nnis/thisisennis.com/htdocs/gallery/post.php on line 46

and this happens to all photos, im sure its something stupid.