/etc/rc.d/init.d/autofs contains the following: if [ -f /etc/$map ] ; then echo "$basecommand file /etc/$map ... else echo "$basecommand yp $map ..." fi This breaks any lookup method that isn't file or yp, namely nisplus and program, and hesiod if you recompile with it.
I forgot that autofs isn't exclusive-arch: i386 anymore.
This should be fixed in autofs-3.1.3-5, which will be in the next Raw Hide release. You will be able to specify in /etc/auto.master: /mnt nisplus:/etc/mnt.map which specifies to use an nisplus map.