I had a working EPiServer 7.1 site.  After running the CMS upgrade process, I am now getting the following error via the site:

Configuration ErrorDescription: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately. 

Parser Error Message: Unrecognized element 'sites'.

Source Error: 

Line 1007:  </hibernate-configuration>
Line 1008:  <episerver.common>
Line 1009:    <sites>
Line 1010:      <site siteId="*">
Line 1011:        <cache defaultProvider="EPiServerCacheExpirationProvider">

From this, I made a guess that the issue was that I hadn't upgraded Community yet.  However, I'm unable to upgrade community. The installer is throwing errors on upgrade.  At first I got the following error:

See the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.ApplicationException: The web.config file for this site does not appear to match the EPiServer schema - could not find a matching <site> node
at EPiServer.Install.WebServer.WebApplication.get_SiteConfigNode()
at EPiServer.Install.WebServer.WebApplication.GetEPiServerCMSConnectionStringName()
at EPiServer.Install.WebServer.WebApplication.get_ConnectionStringNode()
at EPiServer.Install.WebServer.WebApplication.get_SiteDbProvider()
at EPiServer.Install.UI.Wizards.UpgradeSiteWizard.OnStepChanging(UserControl currentStep, Int32 currentStepIndex, UserControl nextStep, Int32 nextStepIndex, Boolean& skipNextStep)
at EPiServer.Community.Install.Wizards.UpgradeSiteWizard.OnStepChanging(UserControl currentStep, Int32 currentStepIndex, UserControl nextStep, Int32 nextStepIndex, Boolean& skipNextStep)
at EPiServer.Install.UI.WizardFrameForm.GetNextStepIndex(Int32 currentStepIndex, Int32 newStepIndex)
at EPiServer.Install.UI.WizardFrameForm.UpdateWizard(Int32 previousStepIndex, Int32 newStepIndex)
at EPiServer.Install.UI.WizardFrameForm.DoButtonAction(ButtonAction action)
at EPiServer.Install.UI.WizardFrameForm.Button2_Click(Object sender, EventArgs e)
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

After some googling, there was a comment that suggested the lack of an xmls might be the cause, so I updated my <episerver.common> node to the following:

<episerver.common xmlns="http://EPiServer.Configuration.EPiServerSection">

But after this, the installer triggers:

See the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.NullReferenceException: Object reference not set to an instance of an object.
at EPiServer.Install.WebServer.WebApplication.IsMatchOnAppPath(XmlNode siteSettingsNode)
at EPiServer.Install.WebServer.WebApplication.GetSiteNode()
at EPiServer.Install.WebServer.WebApplication.get_SiteConfigNode()
at EPiServer.Install.WebServer.WebApplication.GetEPiServerCMSConnectionStringName()
at EPiServer.Install.WebServer.WebApplication.get_ConnectionStringNode()
at EPiServer.Install.WebServer.WebApplication.get_SiteDbProvider()
at EPiServer.Install.UI.Wizards.UpgradeSiteWizard.OnStepChanging(UserControl currentStep, Int32 currentStepIndex, UserControl nextStep, Int32 nextStepIndex, Boolean& skipNextStep)
at EPiServer.Community.Install.Wizards.UpgradeSiteWizard.OnStepChanging(UserControl currentStep, Int32 currentStepIndex, UserControl nextStep, Int32 nextStepIndex, Boolean& skipNextStep)
at EPiServer.Install.UI.WizardFrameForm.GetNextStepIndex(Int32 currentStepIndex, Int32 newStepIndex)
at EPiServer.Install.UI.WizardFrameForm.UpdateWizard(Int32 previousStepIndex, Int32 newStepIndex)
at EPiServer.Install.UI.WizardFrameForm.DoButtonAction(ButtonAction action)
at EPiServer.Install.UI.WizardFrameForm.Button2_Click(Object sender, EventArgs e)
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Can anyone provide some insight?