Chris Own is the guy, he lives in Seattle (or did). Last known address (from the website):
922 N. 93rd St.
Seattle, WA 98103
service@ack-industries.comA few years back he stopped by my house to let me demo a dAck! 2.0 which I ended up buying. He has a PhD. in molecular physics or some crazy thing. He told me he developed the dAck! as a way to work through his doctorate program which was already completed when I met him. I believe he told me that his battery pack is not simply an off-the-shelf unit like most of the guys are using. I wouldn't be surprised if he's quit developing and has moved on with life.
However, I also bet he'd help you get your unit working again. He used to make the battery packs himself at his house. I think he's a stand-up guy and would build you a pack if you can find him. I also bet that you could carefully disassemble the battery pack you have and reverse-engineer it. There are a couple of SLA batteries in there and, what, a couple of caps probably? I doubt there's any magic ether that simply can't be replaced.
Good luck!