Error when publishing Blog

Apr 14, 2011 at 4:03 PM

We're using 4.5.2 with BlogForUmbraco installed - it has been working fine until a few weeks ago.  Now, when we Save and Publish a new blog post, we get the error below, the post remains draft in the content tree, and it is not assigned to date folders.

Plus, worse, it seems to unpublish ALL pages on the site - so the front end shows the "Looks like there's still work to do" standard Umbraco page.

By revisiting the draft blog post on the content tree, it is possible to Save and Publish it again, and this brings everything back to life, and publishes the post and assigns it to datefolders.  But for our clients who are posting entries in their blogs, it's a nasty error to see and takes down the whole site each time.

Any ideas on what's gone wrong and how to fix it?

Here's the error we're getting when we try to publish a post for the first time:

[NullReferenceException: Object reference not set to an instance of an object.]
   umbraco.content.ValidateSchema(String docTypeAlias, XmlDocument xmlDoc) +51
   umbraco.content.AppendDocumentXml(Int32 id, Int32 level, Int32 parentId, XmlNode docXml, XmlDocument xmlContentCopy) +117
   umbraco.content.PublishNodeDo(Document d, XmlDocument xmlContentCopy, Boolean updateSitemapProvider) +217
   umbraco.content.UpdateDocumentCache(Document d) +395
   umbraco.content.UpdateDocumentCache(Int32 pageId) +72
   umbraco.library.UpdateDocumentCache(Int32 DocumentId) +146
   umbraco.cms.presentation.editContent.Publish(Object sender, EventArgs e) +459
   System.EventHandler.Invoke(Object sender, EventArgs e) +0
   umbraco.controls.ContentControl.savePublish(Object Sender, ImageClickEventArgs e) +96
   System.Web.UI.WebControls.ImageButton.OnClick(ImageClickEventArgs e) +108
   System.Web.UI.WebControls.ImageButton.RaisePostBackEvent(String eventArgument) +118
   System.Web.UI.WebControls.ImageButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1565

We posted this error on the umbraco log but didn't get a solution so thought we should post here.

Many thanks for your help.

Kevin