I responded to you on the UBK Fatso thread but didn't realize you'd started a thread over here.
First, I apologize for not covering the basics in the manual, and you're totally justified in feeling frustrated at the lack of simple, clear info on how to hook this shit up. FYI, I'm going to update the manual so future users don't have to deal with this crap the way you have.
Second, part of what's tripping you up is that your ULN (awesome piece btw!) has unorthodox connectors. Most gear has XLR (and maybe 1/4") inputs and outputs like the UBK Fatso, but your ULN has "DB25" connectors because it's the only way they could allow for so many ins and outs on a piece of gear that size.
So what you need are two DB25 Snakes, these are 8-channel snakes with a DB25 connector on one end (to go to your ULN) and XLR connectors on the other (to go to the rack gear you are conecting your ULN to).
First snake is DB25 to (8x) XLR Males, these XLR's go to the Inputs of your UBK Fatso and other gear and the DB25 goes to the Line/Monitor Out 1-8 connector on your ULN. Use XLR 1&2 for your UBK Fatso.
Example: Hosa DTM-803 (3 Meter) | Sweetwater.com
Second snake is DB25 to (8x) XLR Female, these XLR's go to the Outputs of your UBK Fatso and other gear and the DB25 goes to the Line In 1-8 connector on your ULN. Again, use XLR 1&2 for your UBK Fatso.
Example: Hosa DTF-803 (3 Meter) | Sweetwater.com
The good news is when you do the above, your ULN and UBK Fatso will be properly connected.
The bad news is after you properly connect these two devices, you have to then figure out how to properly route the signal via Metric Halo's MIO Console software, which can be a daunting task even for seasoned engineers. But on the plus side their tech support via phone is very helpful, and I know this because they got me up and running when I first bought my Metric Halo interface last year.
Keep us posted, and thanks for your patience while we get you thru this!
Gregory Scott - ubk