I can view the articles I created earlier for the blog module but I can no longer access the blog holder page in admin. I get the error:
Error at line 1324 of ...../framework/model/DataObject.php

Anyone had any experience of this error? Just looking for clues.

Did you install the widget module? I am getting the same error after installing the widget module in SS 3.0.3. If I remove the widget module and rebuild, the error goes away.

Disappointing. I should have just stuck with SS 2.4.7, so far SS3 makes me sad. I love the new admin, but after dealing with performance issues and all of these little problems I need a drink.

You might try the branch of the blog moduleon github 'ss3-fixes', it seems to have fixed the issue for me:

https://github.com/silverstripe/silverstripe-blog/tree/ss3-fixes

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
GET /admin/pages/edit/show/8
Line 670 in /framework/vier/SSViewer.php

Source
if(!$this->chosenTemplates){
$templateList=(is_array($templateList)) ? $templateList:array($templateList);

user_error("Noe of these templates can be found in theme""
.self::current_theme()."":".implode(".ss,",$templateList).".ss,E_USER_WARNING);
}

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?

Thanks,
Samy

Ok. Did get it solved after a fresh install and then using the fixed blog. Apparently "updating" the files and running a dev/build and flush didn't do it...