Just putting a file somewhere does absolutely nothing. You need to add a reference to the file somewhere so that WoW knows to load it. For CrowBar, the proper place to reference AceLocale-3.0 would be in the "libs.xml" file. Open it in Notepad.
Oh. Duh. :) Thanks for that - since the AddOn was erroring because it was looking for a dependency and not finding it, I thought the "looking for" part was already in place. I added an AceLocale-3.0 reference to the 'libs.xml' file and Crowbar no longer errors out on game load (not sure it actually works yet, as I haven't found any container loot, but I'm hopeful).