So, I downloaded the ACE mod ( http://skyrim.nexusmods.com/mods/10037/?). It includes a new archery perk that causes all enemies to stagger 100% of the time when hit with an arrow. This made the game incredibly easy, so I attempted to reverse the effects of the perk. First I tried the removeperk console command. For some reason, this didn't work. So I then typed in player.forceAV bowstaggerbonus 0.10. Again, it didn't work. So then I simply hit the space bar, causing the skill to become "Legendary" (resetting it to level 15 and removing all the perks). Still, it did not work...any help that can be offered would be very appreciated.

You're probably going to get a better answer by posting your question in the comments on the mod's Nexus page.

I think you would need to re-load the game from before you had this unfortunate mod, friend...
Trying to 'reverse' the perk doesn't sound like it's working out so well for you.

I can, however, recommend Duel-Combat Realism. Most wholeheartedly!
Enemies can be staggered - but you can (and will) be staggered by enemies, too.
The game just basically svcks without it...

ACE is not designed to have the perks removed.
IMO, it applies a magic effect and you need to remove THAT.