Same problem here with a fresh install. Tried the blog-fix but now I get a new error message.
[User Warning] None of these templates can be found in theme ": WidgetAreaEditor.ss
Line 670 in /framework/vier/SSViewer.php
$templateList=(is_array($templateList)) ? $templateList:array($templateList);
user_error("Noe of these templates can be found in theme""
This message will only show after a reload of BlogHolder (admin panel) for a second and then somehow autoscrolls down to the admin area which oddly enough still is displayed. I cannot scroll up to the top of the page to read the error message nor can I scroll down to the area where I can usually save changes to the page. So I only get to see a limited part of the page.
The error messages to me hints more in direction of a widget-module problem rather than a blog problem. I am not a code crack so I am pretty lost here and require different blog widgets for a project. Would rather stick to SS3. Anyone else experience this and found a solution?