So at some point I updated the hubspot plugin on my server and it caused the wp-admin section to only give me a white screen. I was able to re-activate all other plugins and the admin panel resumed working.
Things I know:
Version 1.4.2 works fine.
Versions 1.5 - 1.5.3 do not.
It does not work on my production server, but it does work on my local WAMP setup.
I tried debugging as best I could, but I'm not super experienced in debugging these kinds of issues.
Any ideas? It's clearly something about the production server, but I'm at a loss for what, and I don't have any more ideas to go on. I'd be happy to provide more info.