I think this is not an actual issue at this time, but for just case maybe you can try to disable Impersonation (http://support.esri.com/en/knowledgebase/techarticles/detail/36887 ) or you can try to create new AGS WebInstance (ArcGIS Server for the Microsoft .NET Framework 9.3 Help )
Hello Vladimir, I appreciate the reply - this was 5 years ago and several versions ago. 🙂