Wikimedia Bugzilla is closed!

You have to supply a template parameter if you use format=template, so this is in error:
  {{#ask: [[Located in::+]] |format=template }}

This correctly outputs 
  Please provide parameter "template" for query to work.
(good!)  But 

a) The string is hardcoded in SMW_QP_Template.php, it's not internationalized.
b) It doesn't appear with the cool yellow warning icon or as a tooltip.

ResultPrinters don't have a clean way to add their own errors to the query parser's errors, but changing line 33 to something like 
   return smwfEncodeMessages(array(wfMsgForContent('smw_qpneedstemplate')));
helps.
D'oh, I see there's already a note in the SMW_QP_Template.php code // TODO: internationalise, beautify
sorry to file a bug for a TODO.