Red Hat's GNOME desktop has never shipped with associations for word processing documents. I think this is a bug, since the shipped KDE packages install KWord (which IMO is much less mature than AbiWord.) I don't know where mime-type info is stored in GNOME these days, but gnome-vfs sounds like as good a guess as any. Including AbiWord in the default install was filed as bug 49142.
I think the problem is that /usr/share/mime-info/gnome-vfs.keys lists "abiword" in shortlist for application/x-abiword, application/msword, while Red Hat abiword package installs binary as "AbiWord" - gnome-vfs doesn't seem to understand that these are the same app. (I think it should still pick up "open=AbiWord" from abiword.keys, but it seems like it doesn't.) To fix, [see attached patch], or install application as "abiword", or fix gnome-vfs...
Created attachment 29834 [details] Correct app name in shortlist; diff from installed .keys
I think what it all boils down to is that you should sync your spec file with src/pkg/linux/rpm/abisuite.spec-template from AbiWord source tree.
Another problem here is that the mime-info files are inconsistent; abiword.keys contains just application/x-abiword ext: abw but abiword.keys sets up handlers for text/abiword, not application/x-abiword. Also, http://bugzilla.gnome.org/show_bug.cgi?id=59670, is clearly related to this.
*** This bug has been marked as a duplicate of 50924 ***