Description of problem:
Fedora 16 x86_64 has both x86_64 and i686 versions of caribou. gnome-shell package on x86_64 seems to accept a i686 version of caribou to fill the dependency, but it will not work with that arch's version.
Version-Release number of selected component (if applicable):
Thanks for the report, Joonas!
Fixed in gnome-shell-184.108.40.206-2 in git; not doing a build for F16 just for this change, but it will be in the next build.
*** Bug 753649 has been marked as a duplicate of this bug. ***
This requirement isn't being enforced on upgrade from F15; caribou.noarch is being replaced by caribou.i686. See Bug 753649.