Cannot set default for date range

I'm very excited about this module; however I have a discouraging problem. I cannot set the default value for the date range.
I need my site to show a listing of different types of events (each in a different view) from the current date to 1 week hence upon a new user's first arrival. I have gotten the global filter connected to the events views but the only place I can see to set the default for a new user is in the global filter block, and the default dropdown is showing only one option: ' - No default ("All") - '. Putting a php script in the global filter default area, is proving completely ineffectual. I even tried copying one of the example php scripts to completely eliminate the possibility of mistakes in the php script.
In a separate browser that is not logged into the site and with which I have not made any new settings in the global filter, I view the page and the global filter shows today's date in both date areas. It shows today's date even if I use return '2013-01-01--2013-12-31'; in the default php config area. I've looked over the Readme and searched and searched online, and I'm not getting any insight.

The global filter block is being driven by a field:date, and the widget is set to range.

The views are connected with a contextual filter for field:date - start date with Provide Default Value checked and Global Filter (field or search term) selected, and with Allow Relative Date Ranges is checked.

What am I missing here?
Thanks!

P.S.
The php I have for the default setting is:
The php I have in the default box is:

$now = date("m-d-Y h:i a");
$then = date('m-d-Y h:i a',strtotime("+7 days"));
$daterange = $now."--".$then;
return $daterange;