When logged in as host and I click on 'Restart App' under host settings I get the following error:

A critical error has occurred.
Access to the path 'D:\inetpub\domain-name\dnn-folder-name\web.config' is denied.

First thing I thought of was that insufficient permissions had been assigned to ASPNET on the DNN app folder and files that reside in it. My hosting company have diligently reassigned 'modify' rights (and read rights too) to ASPNET but the problem persists. I have run out of ideas on how to next troubleshoot this. Any ideas on what to try next?

Some additional info:

• I moved from a .net 2.0 server to .net 3.5 server last weekend (although I did not make any changes myself to the web.config file since the server move took place). Is this migration behind the problem?
• The site is running DNN v4.9.1
• Thrid party modules installed are:
  • Active Forums v4.1
  • Active Social 1.1
  • Snapsis PageBlaster
• The site is in a shared hosting environemnt (not Godaddy)