The spell description states that an evil creature can not someone under the protection of this spell. Does that mean at all? Or does it just mean that the creature has to make a will save to do it?
You need to read further down in the spell description:
Third, the spell prevents bodily contact by summoned creatures. This causes the natural weapon attacks of such creatures to fail and the creatures to recoil if such attacks require touching the warded creature. Good summoned creatures are immune to this effect. The protection against contact by summoned creatures ends if the warded creature makes an attack against or tries to force the barrier against the blocked creature. Spell resistance can allow a creature to overcome this protection and touch the warded creature.