After upgrading to DNN 4.05.03 from 4.05.01 I get the error shown below logged in the event viewer (I get many of them).  I've also been having trouble while logged in as a Admin or Host account - can't add a page (tab) or module to the portal.  When trying to make Admin or Host level changes to settings, a lot of the time the changes don't take effect and I have to make the changes about 3-4 times before they actually get changed.  Listed below as well is another Page Load Exception I get across many pages when logged in as Admin or Host.  The errors always seem to be related to: "Object reference not set to an instance of an object." - it occurs for many of the pages in the portal.

Help with these errors would be great - thanks.

AssemblyVersion: -1
PortalID: -1
PortalName:
UserID: -1
UserName:
ActiveTabID: -1
ActiveTabName:
RawURL:
AbsoluteURL:
AbsoluteURLReferrer:
UserAgent:
DefaultDataProvider:
ExceptionGUID:
InnerException: Could not load type ''.
FileName:
FileLineNumber: -1
FileColumnNumber: -1
Method:
StackTrace:
Message: System.Web.HttpException: Could not load type ''. ---> System.ArgumentException: String cannot have zero length.at System.Reflection.Assembly.GetType(String name, Boolean throwOnError, Boolean ignoreCase)at System.Web.Compilation.BuildManager.GetType(String typeName, Boolean throwOnError, Boolean ignoreCase)--- End of inner exception stack trace ---at System.Web.Compilation.BuildManager.GetType(String typeName, Boolean throwOnError, Boolean ignoreCase)at DotNetNuke.Framework.Reflection.CreateType(String TypeName, String CacheKey, Boolean UseCache, Boolean IgnoreErrors)
Source:
Server Name:

AssemblyVersion: 04.05.03
PortalID: 0
PortalName: Tanami Photography
UserID: 9
UserName: tchost
ActiveTabID: 36
ActiveTabName: Home
RawURL: /Home/tabid/36/ctl/Tab/Default.aspx
AbsoluteURL: /Default.aspx
AbsoluteURLReferrer: http://www.tanamiphotography.com/Home/tabid/36/ctl/Tab/Default.aspx
UserAgent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.0.04506; InfoPath.1)
DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider
ExceptionGUID: 5c7ee8d9-9529-47a3-9058-cc64837a7fb1
InnerException: Object reference not set to an instance of an object.
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: DotNetNuke.Security.Permissions.Controls.TabPermissionsGrid.GetUsers
StackTrace:
Message: DotNetNuke.Services.Exceptions.PageLoadException: Object reference not set to an instance of an object. ---> System.NullReferenceException: Object reference not set to an instance of an object.at DotNetNuke.Security.Permissions.Controls.TabPermissionsGrid.GetUsers()at DotNetNuke.Security.Permissions.Controls.PermissionsGrid.CreateChildControls()at System.Web.UI.Control.EnsureChildControls()at System.Web.UI.Control.FindControl(String id, Int32 pathOffset)at System.Web.UI.Control.FindControl(String id, Int32 pathOffset)at System.Web.UI.Control.FindControl(String id, Int32 pathOffset)at System.Web.UI.Control.FindControl(String id, Int32 pathOffset)at System.Web.UI.Control.FindControl(String id, Int32 pathOffset)at System.Web.UI.Page.FindControl(String id)at System.Web.UI.Page.ProcessPostData(NameValueCollection postData, Boolean fBeforeLoad)at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)--- End of inner exception stack trace ---
Source:
Server Name:

I tried running the script to cleart the search index:

delete {databaseOwner}{objectQualifier}SearchItemWordPosition
delete {databaseOwner}{objectQualifier}SearchItemWord
delete {databaseOwner}{objectQualifier}SearchWord
delete {databaseOwner}{objectQualifier}SearchItem

I still get the following logged under the Event Viewer (lots of them - pages of the same error):

AssemblyVersion: -1
PortalID: -1
PortalName:
UserID: -1
UserName:
ActiveTabID: -1
ActiveTabName:
RawURL:
AbsoluteURL:
AbsoluteURLReferrer:
UserAgent:
DefaultDataProvider:
ExceptionGUID:
InnerException: Value cannot be null. Parameter name: type
FileName:
FileLineNumber: -1
FileColumnNumber: -1
Method:
StackTrace:
Message: System.ArgumentNullException: Value cannot be null. Parameter name: type at System.Activator.CreateInstance(Type type, Boolean nonPublic) at DotNetNuke.Framework.Reflection.CreateObject(String TypeName, String CacheKey) at DotNetNuke.Services.Search.ModuleIndexer.GetModuleList(Int32 PortalID)
Source:
Server Name:

Another thing I've noticed about my portal in that when I create a page (tab) or add a new module to a page the page or module isn't visible until I refresh a few times - or clear the cache and restart the portal while logged in as a host.  Makes me think that the DNN cache isn't working properly ?  If I add a page and leave the site alone for about an hour or so the new page will appear of the navigation menu - DNN cache has cleared itself and or the IIS application pool has recycled ?? - not sure what causes a new page or module not to be immediately visible while logged in as an Admin or Host.  Strange behaviour !!

Tried the script:

UPDATE DesktopModules
SET SupportedFeatures = 0
WHERE SupportedFeatures = -1

I'm still getting the errors.  Some other guys have started posting similar Event log errors in this forum as well - I haven't found an answer yet.