Just open the .bat file in notepad, you'll see all legit ace bat files simply "unpack" or copy the libraries and sub folders into the root addon directory to so it works as a proper unembedded load on demand.
Couple of other things:
1: Always run a virus checker, Avira Anti Vir Personal is currently the best freeware one at the moment imo.
2: Only download mods from major addon sites specifically:
www.curse-gaming.com/wow/,
http://ui.worldofwar.net,
www.wowinterface.com
3: If you are downloading Ace2 mods directly from their svn repository (files.wowace.com etc) be aware they are beta mods and constantly being updated multiple times during the day and so on