I just moved some sites over to my new windows 2008 server.  The move was very easy to do and I thought everything was fine, but I do have an error with RSS feeds in Simple Gallery.  I get the following error.  I likely have a setting to be adjusted in IIS, but I am new to it and am hoping someone can offer advice.  When I find the answer, I will post here for others to find.  News Articles seems to have an issue too where the feeds don't work but no error is thrown.  Property Agent feeds work fine.  This is happening on more than one DNN installation and more than one version of Simple Gallery.  All was well on the old server which is why I suspect IIS7 as the culprit.

AssemblyVersion: 04.08.02
PortalID: 0
PortalName: Lens Cove Marina
UserID: -1
UserName:
ActiveTabID: 36
ActiveTabName: Home
RawURL: /DesktopModules/SimpleGallery/RSS.aspx?t=61&m=381&tm=70&MaxCount=10&portalid=0
AbsoluteURL: /DesktopModules/SimpleGallery/RSS.aspx
AbsoluteURLReferrer: http://www.lenscove.com/PhotoGalleries.aspx
UserAgent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; WOW64; SLCC1; .NET CLR 2.0.50727; .NET CLR 3.0.04506)
DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider
ExceptionGUID: 4f4cbbcc-e266-4ea3-9b66-878e691a55d7
InnerException: Unhandled Error:
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: System.Security.Cryptography.CryptoAPITransform.TransformFinalBlock
StackTrace:
Message: System.Exception: Unhandled Error: ---> System.Security.Cryptography.CryptographicException: Length of the data to decrypt is invalid. at System.Security.Cryptography.CryptoAPITransform.TransformFinalBlock(Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount) at System.Security.Cryptography.CryptoStream.FlushFinalBlock() at System.Web.Configuration.MachineKeySection.EncryptOrDecryptData(Boolean fEncrypt, Byte[] buf, Byte[] modifier, Int32 start, Int32 length, Boolean useValidationSymAlgo) at System.Web.Security.FormsAuthentication.Decrypt(String encryptedTicket) at DotNetNuke.Services.Syndication.RssHttpHandlerHelper.ParseChannelQueryString(HttpRequest request, String& channelName, String& userName) at DotNetNuke.Services.Syndication.RssHttpHandlerBase`3.System.Web.IHttpHandler.ProcessRequest(HttpContext context) at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) --- End of inner exception stack trace ---
Source:
Server Name: MAIL

Answering my own post.

In IIS 7, creating a new site is dead-easy, it seems to do everything for you including creating a new app pool for every site.  By default the App Pools are created in "Integrated" Mode (Managed Pipeline Mode)  I had to change to "Classic" Mode.  DNN 4.8.2 runs just fine in Integrated mode as it is supposed to, but the RSS feed in Simple Gallery is not happy there.

To fix:

Go to the Application Pools in IIS. Select the Application Pool that you are concerned with. From the Actions menu on the right, click on the "Basic Settings" link.  You will see a dropdown setting for "Managed Pipeline Mode".  Change that from "Integrated" to "Classic". 

Mike