Quick answer: upgrade your Fedora!
This is why Linux comes in distros. When you install programs from source, you are left with the job of ensuring that all their requirements are met. You are short of one file (GTKSPELL) and need two upgrading (ndesk-dbus, ndesk-dbus-lib).
Try updating your tomboy with
yum update tomboy
You might find the Fedora repository no longer copes with Fedora 5, but no harm can be done if that is the case.