I need some tips to help me in the battle with the Shadow jailor and the two skeleton lords he has with him.
My party is a 10th barbarian, 9th level vagrant, 11th level auramaster, 7fighter/10cleric Anomen, 10thief/10illusionist Jan jansen, and 11th level mage nalia.

Really once the battle commences i just simply get hammered... i've tried most of the tactics i've used so far but the skeleton lords and jailor have high magic resistance and i dont have the spell lower resistance with me and my summons only really last seconds against them.

My advice would be to leave this battle for latter ( unless you want mazzy), since even after this battle things only get even more difficult (like liches with skeleton lords), and i am sure there are easier places that you can go to get more xp and loot than this battle grants.Regardings tactics i can't offer you much since i never faced skeleton lords that early, but with a mage the only way you cant hurt them is with sunfire and fire shield red, but it won't do much though, you can also use your mages with mirror image and stoneskin near the skeletons so that they soak up some hits instead of the of the warriors but be careful because stone skin runs out fast vs them.Your warriors should be be buffed with haste and clerical spells that improve thaco (bless , aid, etc)and have drunk a potion of strengh each one, heroism potions also improve thaco and give some life.While the skeleton is bashing the stoneskined mage and/or summons you should focus all your warriors on one skeleton with bludeogning weapons.If you can't even kill 1 this way without someone getting owned i suggest you come later.Also the jailor, archons shield can be dispeled by secret word spell, and blade barrier by breach.One more thing, lower resistance would be useless in this battle since your low lv, your mage would only be able to lower it by 20-21% which is pretty insignificant since i think they have around 90%? not really sure,anyway by the time you lowering one's resistance to a decent value either you already bitting the dust or they are.Even if you actually lowered, you don't have decent damage spells that you cant throw at them yet.

In general, whenever you encounter Skeleton Lords in any battle, it's wise to concentrate on killing them before other enemies, because S. Lords have very good offensive power but not very decent defensive abilities.

As a general hint (not merely for S. Lords but for all other creature types), it's wise to have various weapons which inflict different damage types with yourself. Change your weapons and try to figure out the best weapon type against each creature type (i.e. try to figure out whether the creature is most vulnerable to blunt weapons or slashing or piercing). Do this during the battle and inside the game (not outside the game and by looking up the creature's file in an editor; the latter is cheating).