I'm currently using v. 04.04.03 of the forum and get the following exception for one thread:

AssemblyVersion: 04.07.00
PortalID: 4
PortalName: Forsvarsdialog
UserID: 1
UserName: host
ActiveTabID: 116
ActiveTabName: Debatt
RawURL: /Debatt/tabid/116/forumid/11/scope/threads/Default.aspx
AbsoluteURL: /Default.aspx
UserAgent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; SLCC1; .NET CLR 2.0.50727; .NET CLR 3.0.04506; InfoPath.2; FDM)
DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider
ExceptionGUID: c6419f14-f50e-4859-bdde-850da5b4bb37
InnerException: Value cannot be null. Parameter name: value
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: System.Web.Caching.CacheEntry..ctor
StackTrace:
Message: System.ArgumentNullException: Value cannot be null. Parameter name: value at System.Web.Caching.CacheEntry..ctor(String key, Object value, CacheDependency dependency, CacheItemRemovedCallback onRemovedHandler, DateTime utcAbsoluteExpiration, TimeSpan slidingExpiration, CacheItemPriority priority, Boolean isPublic) at System.Web.Caching.CacheInternal.DoInsert(Boolean isPublic, String key, Object value, CacheDependency dependencies, DateTime utcAbsoluteExpiration, TimeSpan slidingExpiration, CacheItemPriority priority, CacheItemRemovedCallback onRemoveCallback, Boolean replace) at System.Web.Caching.Cache.Insert(String key, Object value, CacheDependency dependencies) at DotNetNuke.Services.Cache.FileBasedCachingProvider.FBCachingProvider.Insert(String CacheKey, Object objObject, Boolean PersistAppRestart) at DotNetNuke.Common.Utilities.DataCache.SetCache(String CacheKey, Object objObject) at DotNetNuke.Modules.Forum.ThreadInfo.GetThreadInfo(Int32 ThreadID) at DotNetNuke.Modules.Forum.Threads.RenderThreadInfo(HtmlTextWriter wr, Boolean AggregatedView)

The result of this error is that the forum post list is malformatted and not all threads are listet. When you click the post at the end of the list, the application states that the value cannot be NULL and the post is not displaid. You can see for your self at http://www.forsvarsdialog.no/Debatt/tabid/116/forumid/11/scope/threads/Default.aspx

I have looked in the most obvious places in the database tables and found several entries with value NULL where my guess would be there should be a value. However, changing any values to a proper value does not fix the issue.

Any ideas? Please?

I have identical symptoms in a site I migrated from ActiveForums. Maybe half a dozen threads out of twenty thousand or so break the page, and generate that exception when you click on them.

Mine have valid author IDs, and their database records look no different to that of perfectly good posts: all good records in the forum_posts table and the forum_threads table...

This can be caused by having a forum post by a user who does not have an entry in the Forum_Users table.