• your site is ASP.net based, and you are using ASP.net URL rewriting
• When accessing WEBSTATS or FTPSTATS from plesk you get one of the following errors:
  • with customErrors = On (or remoteonly)
    •  
  • with customErrors = Off

    • Server Error in '/' Application.

      ---

      Configuration Error

      Description: 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: An error occurred loading a configuration file: Failed to start monitoring changes to 'E:\inetpub\vhosts\yourdomain.com\statistics\webstat\web.config' because access is denied.
      
      Source Error:
      
      

      [No relevant source lines]

      
      Source File: E:\inetpub\vhosts\yourdomain.com\statistics\web.config    Line: 0

    • Server Error in '/' Application.

      ---

      Configuration Error

      Description: 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: An error occurred loading a configuration file: Failed to start monitoring changes to 'E:\inetpub\vhosts\yourdomain.com\statistics\webstat\web.config' because access is denied.
      
      Source Error:
      
      

      [No relevant source lines]

      
      Source File: E:\inetpub\vhosts\yourdomain.com\statistics\webstat\web.config    Line: 0

    • Server Error in '/' Application.

      ---

      Configuration Error

      Description: 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: An error occurred loading a configuration file: Failed to start monitoring changes to 'E:\inetpub\vhosts\yourdomain.com\statistics\webstat\web.config' because access is denied.
      
      Source Error:
      
      

      [No relevant source lines]

      
      Source File: E:\inetpub\vhosts\yourdomain.com\statistics\ftpstat\web.config    Line: 0

The problem is due to your asp.net url rewrite function... it's causing ASP.net to look for a web.config at the (ftproot)\statistics folder (because this is where the "/plesk-stat/webstat" virtual folder points to... and the worker process user (IWPD) doesn't have permissions on that folder because it's outside of the webroot (httpdocs).

(we have 2 users for your site code... the IUSR_xxxx is for html code, php code, some asp.net actions, the anonymous user on your site in IIS... the IWPD_xxxx is for ASP and some asp.net actions, the identity assigned to your application pool/worker process...  just for clarification on what is meant by "IWPD user").

So this is just an expected side effect of implementing this ASP.net URL rewrite function within the Plesk environment (unique to how Plesk sets up access to the stats directories.  I.e., even though you don't have any rewrite rules applying to this URL, asp.net still has to scan ANY the URL in EVERY request... and as such, it's touching this folder when that request comes in.... looking for an application specific web.config file over there (which is the nature of asp.net).

The solution, is to simply give the IWPD user read access to the statistics, statistics\webstat, and statistics\ftpstat folders within your directory structure on our server.  Please submit a support request referencing this article, if you need this performed for you.