User: Created date argument

I tried adding to users.views.inc the same same data as the comments patch (replacing comments with users)
e.g.
$data [users]['timestamp_fulldate'] etc with the same handlers. The options appear under arguments in views UI but they produce an error...

Can you point me in the right direction?

Here is my user.view.inc (my bit at line 185) http://pastebin.com/ViDBQHB5.

Error:
An AJAX HTTP error occurred.
HTTP Result Code: 500
Debugging information follows.
Path: /?q=admin/structure/views/ajax/preview/users_per_month&render=overlay
StatusText: Service unavailable (with message)
ResponseText: PDOException: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'users.timestamp' in 'field list': SELECT COUNT(*) AS expression
FROM
(SELECT DATE_FORMAT((DATE_ADD('19700101', INTERVAL users.timestamp SECOND) + INTERVAL 0 SECOND), '%Y%m') AS timestamp_year_month, 1 AS expression
FROM
{users} users
GROUP BY timestamp_year_month) subquery; Array
(
)
in views_plugin_pager->execute_count_query() (line 140 of /Applications/XAMPP/xamppfiles/htdocs/lot/sites/all/modules/views/plugins/views_plugin_pager.inc).