Sample Edit Form: non-numeric label raises error

[graik]

entering "A" in the displayID field raises an Exception:

ValueError at /rotmic/chemicalsample/824/edit/

need more than 2 values to unpack

Request Method: POST
Request URL: http://strube.herokuapp.com/rotmic/chemicalsample/824/edit/
Django Version: 1.6.11
Exception Type: ValueError
Exception Value:

need more than 2 values to unpack

Exception Location: /app/rotmic/forms/sampleForms.py in clean_displayId, line 106