I think this will be an continuing issue for Open office users who upgrade via the distro-sync option to dnf.

After the upgrade openoffice would crash after a brief flash of the start up splash screen. So after much searching I found this solution on the AOO forum:

Do you have gtk2 libraries installed?
Try the following on a terminal:

~]$ ldd -v /opt/openoffice4/program/libvclplug_gtk.so

In my system, this reports a missing library:

...
libgdk_pixbuf_xlib-2.0.so.0 => not found
...

Find the package which provides this library, and install it:

[root@localhost ~]# dnf whatprovides */libgdk_pixbuf_xlib-2.0.so.0
Last metadata expiration check: 19:02:19 ago on Sun Jul 24 18:10:21 2016.
gdk-pixbuf2-xlib-2.34.0-1.fc24.i686 : Additional library for using gdk-pixbuf with bare xlib
Repo : fedora

gdk-pixbuf2-xlib-2.34.0-1.fc24.x86_64 : Additional library for using gdk-pixbuf with bare xlib
Repo : fedora

[root@localhost ~]# dnf install gdk-pixbuf2-xlib

Do the same with every missing library. Then, export the following variables:

~]$ export SAL_USE_VCLPLUGIN="gtk"
~]$ export OOO_FORCE_DESKTOP="gnome"

Now run AOO on that terminal
Add the grep "not found" search term to the end of the ~]$ ldd line so as to get to the point without hundreds of lines of confirmed links, you just want what is not found, example below:

~]$ ldd -v /opt/openoffice4/program/libvclplug_gtk.so | grep "not found"

After following these directions AOO starts up fine.