We are trying to integrate nForum 1.7 with Umbraco v6.1.6 (Assembly version: 1.0.5021.24867). Everything is working well, except for when people try to delete posts. When you try to delete a post a 500 error is thrown. The message for the error is:

Object reference not set to an instance of an object.

With a stack trace:

[NullReferenceException: Object reference not set to an instance of an object.]
nForum.BusinessLogic.Models.Forum.MapForumNodeToModel(IPublishedContent forumRoot) +71 nForum.BusinessLogic.Models.Forum..ctor(Nullable1 overideNodeId) +140
nForum.BusinessLogic.Helpers.MainForumSettings(Nullable1 overideRoot) +211 nForum.BusinessLogic.BaseForumUsercontrol.getSettings() +76 nForum.usercontrols.nForum.ForumDeletePost.DeletePost() +1715
nForum.usercontrols.nForum.ForumDeletePost.PageLoad(Object sender, EventArgs e) +50 System.Web.UI.Control.LoadRecursive() +70
System.Web.UI.Control.LoadRecursive() +189
System.Web.UI.Control.LoadRecursive() +189
System.Web.UI.Control.LoadRecursive() +189
System.Web.UI.Control.LoadRecursive() +189
System.Web.UI.Control.LoadRecursive() +189
System.Web.UI.Control.LoadRecursive() +189
System.Web.UI.Control.LoadRecursive() +189
System.Web.UI.Control.LoadRecursive() +189
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3177

Does anybody know what the cause of this problem is?