We have a productionwebsite, that started throwing errors lately, it seems to have to do with cache objects being created while they already exist, does this ring any bells?

<!--
 /* Font Definitions */
 @font-face
    {font-family:"Cambria Math";
    panose-1:2 4 5 3 5 4 6 3 2 4;
    mso-font-charset:1;
    mso-generic-font-family:roman;
    mso-font-format:other;
    mso-font-pitch:variable;
    mso-font-signature:0 0 0 0 0 0;}
@font-face
    {font-family:Calibri;
    panose-1:2 15 5 2 2 2 4 3 2 4;
    mso-font-alt:"Arial Rounded MT Bold";
    mso-font-charset:0;
    mso-generic-font-family:swiss;
    mso-font-pitch:variable;
    mso-font-signature:-520092929 1073786111 9 0 415 0;}
@font-face
    {font-family:Verdana;
    panose-1:2 11 6 4 3 5 4 4 2 4;
    mso-font-charset:0;
    mso-generic-font-family:swiss;
    mso-font-pitch:variable;
    mso-font-signature:-1593833729 1073750107 16 0 415 0;}
@font-face
    {font-family:"Lucida Console";
    panose-1:2 11 6 9 4 5 4 2 2 4;
    mso-font-charset:0;
    mso-generic-font-family:modern;
    mso-font-pitch:fixed;
    mso-font-signature:-2147482993 6144 0 0 31 0;}
 /* Style Definitions */
 p.MsoNormal, li.MsoNormal, div.MsoNormal
    {mso-style-unhide:no;
    mso-style-qformat:yes;
    mso-style-parent:"";
    margin:0cm;
    margin-bottom:.0001pt;
    mso-pagination:widow-orphan;
    font-size:11.0pt;
    font-family:"Calibri","sans-serif";
    mso-fareast-font-family:Calibri;
    mso-fareast-theme-font:minor-latin;}
a:link, span.MsoHyperlink
    {mso-style-priority:99;
    color:blue;
    text-decoration:underline;
    text-underline:single;}
a:visited, span.MsoHyperlinkFollowed
    {mso-style-noshow:yes;
    mso-style-priority:99;
    color:purple;
    mso-themecolor:followedhyperlink;
    text-decoration:underline;
    text-underline:single;}
.MsoChpDefault
    {mso-style-type:export-only;
    mso-default-props:yes;
    font-size:10.0pt;
    mso-ansi-font-size:10.0pt;
    mso-bidi-font-size:10.0pt;}
@page WordSection1
    {size:612.0pt 792.0pt;
    margin:70.85pt 70.85pt 70.85pt 70.85pt;
    mso-header-margin:35.4pt;
    mso-footer-margin:35.4pt;
    mso-paper-source:0;}
div.WordSection1
    {page:WordSection1;}
-->

Server Error in '/' Application. 

This document already has a
'DocumentElement' node. 
Description: An unhandled exception occurred during the execution of the current web
request. Please review the stack trace for more information about the error and
where it originated in the code. 

Exception Details: System.InvalidOperationException: This document
already has a 'DocumentElement' node.

Source Error: 

 

  

  
An unhandled exception was generated during the execution of the
  current web request. Information regarding the origin and location of the
  exception can be identified using the exception stack trace below. 
  
 

Stack Trace: 


 

  

  
 
  
[InvalidOperationException: This document already has a
  'DocumentElement' node.]
  
   System.Xml.XmlDocument.IsValidChildType(XmlNodeType
  type) +3957861
  
   System.Xml.XmlDocument.AppendChildForLoad(XmlNode
  newChild, XmlDocument doc) +28
  
   System.Xml.XmlLoader.LoadDocSequence(XmlDocument
  parentDoc) +37
  
   System.Xml.XmlLoader.Load(XmlDocument doc,
  XmlReader reader, Boolean preserveWhitespace) +129
  
   System.Xml.XmlDocument.Load(XmlReader reader) +108
  
   System.Xml.XmlDocument.Load(String filename) +87
  
  
  umbraco.cms.businesslogic.web.Access.get_AccessXml() +154
  
   umbraco.cms.businesslogic.web.Access.getPage(Int32
  documentId) +15
  
   umbraco.cms.businesslogic.web.Access.IsProtected(Int32
  DocumentId, String Path) +146
  
   umbraco.requestHandler..ctor(XmlDocument
  _umbracoContent, String url) +3445
  
   umbraco.UmbracoDefault.Page_PreInit(Object sender,
  EventArgs e) +818
  
  
  System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o,
  Object t, EventArgs e) +14
  
   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object
  sender, EventArgs e) +35
  
   System.EventHandler.Invoke(Object sender, EventArgs
  e) +0
  
   System.Web.UI.Page.OnPreInit(EventArgs e) +8694814
  
   System.Web.UI.Page.PerformPreInit() +31
  
   System.Web.UI.Page.ProcessRequestMain(Boolean
  includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +282
  
 


Version Information: Microsoft .NET Framework Version:2.0.50727.3053;
ASP.NET Version:2.0.50727.3053 


 

  

  
Request
  Details
  
 
 

  

  
Session
  Id:
  
  

  
g5d05n45djfy4o45jrlypg45
  
  

  
Request
  Type:
  
  

  
GET
  
  
 
  
 
  
 
  
 
  
 
  
 
 
 

  

  
Time
  of Request:
  
  

  
16/08/2010 12:12:14
  
  

  
Status
  Code:
  
  

  
500
  
  
 
  
 
  
 
  
 
  
 
  
 
 
 

  

  
Request
  Encoding:
  
  

  
Unicode (UTF-8)
  
  

  
Response
  Encoding:
  
  

  
Unicode (UTF-8)
  
  
 
  
 
  
 
  
 
  
 
  
 
 


 

 

  

  
Trace
  Information
  
 
 

  

  
Category
  
  

  
Message
  
  

  
From
  First(s)
  
  

  
From
  Last(s)
  
  
 
  
 
  
 
  
 
  
 
  
 
 
 

  

  
aspx.page
  
  

  
Begin PreInit
  
  
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
 
 

  

  
umbracoInit
  
  

  
handling request
  
  

  
0,0209018941337438
  
  

  
0,020902
  
  
 
  
 
  
 
  
 
  
 
  
 
 
 

  

  
request handler
  
  

  
current url '/nl/het-project'
  
  

  
0,193826627615301
  
  

  
0,172925
  
  
 
  
 
  
 
  
 
  
 
  
 
 
 

  

  
umbracoRequestHandler
  
  

  
xpath: '/root/node/node [@urlName = "nl"]/node
  [@urlName = "het-project"] | /root/node [@urlName =
  "het-project"]'
  
  

  
0,263074831822587
  
  

  
0,069248
  
  
 
  
 
  
 
  
 
  
 
  
 
 
 

  

  
umbracoRequestHandler
  
  

  
Just before xPath query (False, '/root/node/node [@urlName =
  "nl"]/node [@urlName = "het-project"] | /root/node
  [@urlName = "het-project"]')
  
  

  
0,263177240465196
  
  

  
0,000102
  
  
 
  
 
  
 
  
 
  
 
  
 
 
 

  

  
umbracoRequestHandler
  
  

  
pageXPathQueryStart: '/root'
  
  

  
0,263248775725443
  
  

  
0,000072
  
  
 
  
 
  
 
  
 
  
 
  
 
 
 

  

  
umbracoRequestHandler
  
  

  
Adding to cache... ('/nl/het-project')
  
  

  
0,264494494327575
  
  

  
0,001246
  
  
 
  
 
  
 
  
 
  
 
  
 
 
 

  

  
umbracoRequestHandler
  
  

  
After xPath query
  
  

  
0,264564417650077
  
  

  
0,000070
  
  
 
  
 
  
 
  
 
  
 
  
 
 
 

  

  
umbracoRequestHandler
  
  

  
Access checking started
  
  

  
0,264712084544781
  
  

  
0,000148
  
  
 
  
 
  
 
  
 
  
 
  
 
 
 

  

  
Unhandled Execution Error
  
  

  


  This document already has a 'DocumentElement' node.

    at System.Xml.XmlDocument.IsValidChildType(XmlNodeType type)

    at System.Xml.XmlDocument.AppendChildForLoad(XmlNode newChild,
  XmlDocument doc)

    at System.Xml.XmlLoader.LoadDocSequence(XmlDocument parentDoc)

    at System.Xml.XmlLoader.Load(XmlDocument doc, XmlReader reader,
  Boolean preserveWhitespace)

    at System.Xml.XmlDocument.Load(XmlReader reader)

    at System.Xml.XmlDocument.Load(String filename)

    at umbraco.cms.businesslogic.web.Access.get_AccessXml()

    at umbraco.cms.businesslogic.web.Access.getPage(Int32 documentId)

    at umbraco.cms.businesslogic.web.Access.IsProtected(Int32
  DocumentId, String Path)

    at umbraco.requestHandler..ctor(XmlDocument _umbracoContent,
  String url)

    at umbraco.UmbracoDefault.Page_PreInit(Object sender, EventArgs
  e)

    at System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp,
  Object o, Object t, EventArgs e)

    at System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object
  sender, EventArgs e)

    at System.EventHandler.Invoke(Object sender, EventArgs e)

    at System.Web.UI.Page.OnPreInit(EventArgs e)

    at System.Web.UI.Page.PerformPreInit()

    at System.Web.UI.Page.ProcessRequestMain(Boolean
  includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
  
  

  
0,333269368907132
  
  

  
0,068557