According to the Information in the Node Window of Core, the blocksdir is C:\Users\powpig\AppData\Roaming\Bitcoin\blocks.

If I set the datadir in Armory to that same C:\Users\powpig\AppData\Roaming\Bitcoin\blocks, I can get Armory to go Online and it will begin to download a duplicate blockchain

As you say it's failing to read the data in that folder while the datadir in Armory is set to the default C:\Users\powpig\AppData\Roaming\Bitcoin, I have no idea if any permission has been given, it previously worked fine, nothing has been changed, and if I can get it to read data by just changing the datadir location, it doesn't seem like that's the problem.  Am I wrong about that?