Thank you for the replies. I had tried multiple cables, and multiple USB ports. I had also deleted the Keylab 88 from MIDI Devices on the macs audio/midi setup app, and then initiated an update so I could plug in again and have the mac write a fresh instance for the Keylab. I also downloaded a midi app to track whether midi data was coming from the Keylab or not, and while the computer could clearly see the Keylab plugged in there was no MIDI data being sent to the mac (I cross verified with my minilab, where plenty of midi data was sent to the app). Nothing was working...
However I DID end up getting this going again last night. It took hooking it up to an older mac I happened to have, which basically has a brand new hard drive with nothing on it. I downloaded MIDI control from Arturia, and was running into the same error even on that machine. I ended up downloading an older version of the firmware from the archives, and one of them actually did install on the keylab (oddly it never showed as successful, I just happened to notice that the display in Midi control showed a firmware version rather than "unknown" like it had been displaying. From there I was able to upgrade again to the newest firmware and I'm back in action here.
thanks!