On a new build of CentOS 7, MariaDB 10.1, Python 2.7.5, CherryPy 3.2.4 and Filelocker 2.6.1 I couldn't get Bulk User Creation to work. The gui error was "Missing request key!!" and no entries in the error log. I "fixed" the issue by changing line 35 in <filelocker root="">/controller/AdminController.py.
I know this isn't a suitable fix, but I'm not a developer and it got Bulk User Creation to work which made me happy.
The Filelocker.request function automatically includes the required key for POST requests. But rather than using Filelocker.request, the .csv uploader for bulk users utilizes an external uploader (http://github.com/Valums-File-Uploader/file-uploader), and so the required key (requestOrigin) isn't sent along.
A fix is to edit this javascript file:
<filelocker_root>/static/js/admin.js
Add requestOrigin as an additional parameter in the setParams function at line 1012. Now the POST data will include the key that the backend Python code is looking for.