Hi Daniel.
Yes, i remember the previous round.  Did you pinpoint this to the 32bit
libgdk_pixbuf on your machine?
To do a quick check now, grab an updated "lw personal" and run a small
test-script:
(let ((test-image "/some/tiff/image.tiff"))
  (capi:contain (make-instance 'capi:output-pane
                               :display-callback
                               #'(lambda (pane &rest x)
                                   (let ((img (gp:load-image pane test-image)))
                                     (gp:draw-image pane img 0 0))))))
and just to be sure, substitute with a few other formats (jpg, png, bmp,
whatever).
    D> I guess you are still using TIFF images for the logo and stuff?
Yes.
    D> Could you tell me which version of LispWorks you are currently
    D> using,
lw: (lisp-implementation-version): 6.1.1
    D> and wich version of libgdk_pixbuf 32bit is installed in your
    D> 64bit environment?
libgdk_pixbuf-2.0.so.0.3000.3
If you observe the same error vs. loading tiff's, perhaps try checking
further out in the loading, somewhere in the output from this:
  $ gdk-pixbuf-query-loaders-32 | grep -A5 tiff
and see if there's something there.
Please tell me where you get.
-anders