DK has 6 skill points in one handed damage/slashing and a short sword. Hereo has 5 skill points in one handed damage/crushing and has a spiked club. Now they both have shields is that a problem?
Putting points in damage but not in accuracy may be why you aren't hitting the DKs.
The other thing is, are your points being used in the One Handed skill or the One Handed & Shield skill? If the former, none of your bonuses are working and you are effectively attacking the DKs with no melee skills at all - a sure recipe for disaster and death.
The DKs are very tough opponents.
