Hitting this at 77b23035c3c2e7608b7cab92c189aca1d1b45a79 (let me know if it's fixed since then).
Basically go to a workboard and under the column drop down, click "Create Column". In the Chrome developer tools network tab, it shows /maniphest/create/ returning a 500 error with just this text.
Doesn't repro for me at HEAD and I'm pretty sure I remember fixing this. I presume you can't reproduce on this install?
Works on this install so it looks like I need to upgrade.
(As a side note, "Create Task" in that drop down shows as greyed out in this install, even though I can use it to create tasks?)
I think workboard permissions are a little iffy until T6502.
Presuming this is resolved, yell if not.