It's not clearly stated on who is immune to Beguile. (At least not where I looked)
Also, the one time it does work, the enemy that I used it on actually attacked us still with a Sandstorm.
AOE's are not affected by beguile because those spells will hit the enemy and their teammate no matter whose team they are on. For example if you are beguiled and used an AOE, then you will hit all the people on the opposing team plus some people on your team.
I have problems with this too; the way I'm told it is supposed to work, only works when someone uses it on me! LOL A little animation of it in use doesn't tell you what is supposed to happen and to who.
