[CapedCrusader]

OK, I was right. This had to change a bit. With the addition of the multiple Arcane Backgrounds, you have to tell it which Arcane Background the Power attaches to. So you have to add a tag to the bootstrap for this. Each Arcane Background has an identifier tag that goes with it. The bootstrap goes on the Arcane Background Edge, not the Arcane Background itself. Here's an example of adding the Blind Power to the Magic Arcane Background:

  <thing
    id="edgArcMagSWADE"
    name="Arcane Background: Magic"
    compset="Edge"
    isunique="yes"
    summary="Gain the Magic arcane background"
    description="{b}Note:{/b} This is the Edge your character must purchase to possess the &quot;Magic&quot; arcane background and cast spells.">
    <fieldval field="shortname" value="Arcane Magic"/>
    <usesource source="AdventureEd"/>
    <tag group="EdgeType" tag="Background"/>
    <tag group="MinRank" tag="0"/>
    <tag group="Arcane" tag="Magic"/>
    <bootstrap thing="arcMagicSWADE"/>
    <bootstrap thing="powBlindSWADE">
      <autotag group="Arcane" tag="arcMagicSWADE"/>
      </bootstrap>
    </thing>

Now, finding that tag can be tricky. One way is to add the AB to a Hero, then add a Power to it and then Show Debug Tags on the Power. It'll be right on top. It's also the tag for the Arcane Background itself that you bootstrapped to the Edge, you can see it on the line above.