I had the exact same experience just now - also using a local XAMPP install. The problem is caused by a php version incompatibility. Current XAMPP uses php version 5.4.7 and this version has tightened up the use of not properly instantiating objects and has changed the way you code for passing a variable by reference.
The first error can be fixed by explicitly instantiating the object. Change line 76 in blueprint.php from
$placester_blueprint = new stdClass();
There is one more occurrence of this problem. Before line 136 in blueprint\partials\get-listings-search-form.php add:
if ( !isset( $form_data ) )
$form_data = new stdClass();
The error on line 139 is caused by incorrect (as of php 5.3) use of "pass by reference". It is the function definition that needs to specify that a call is to be made by reference and not the call to the function (see also Kernighan and Ritchie - 1978 ;o). There are a few other places where this needs to be fixed. Simply remove the '&' from the call and (if not already present) add the '&' to the function definition.
line 139, 142, 156, 170 in property-details.php - amenities_but and translate_amenities
line 18 in compatibility.php - get_valid_property_list_fields
line 20 in formatting.php - validate_number
line 268 in blueprint/functions/formatting.php - amenities_but
Next problem: the "Install it Now" button on the admin page returns an object not found, however I was able to install the plugin manually.
And here comes the next problem: need to confirm email address and that gets stuck. So head over to the Placester website, create a new account and copy the API key to paste into my WP site. Unfortunately the plugin refuses to recognise it as a valid API key.
Two hours of debugging later and I'm now faced with a nag-screen every 5 seconds. Time to throw in the towel...