title: Orchard CMS Error "ValueFactory attempted to access the Value property of this instance"?
body: <p>I I am using orchard 1.8.1 and try to install the theme Bootstrap and it gives me the following errors. Can anyone help me out?
  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. </p>
  
  <p>Exception Details: System.InvalidOperationException: ValueFactory attempted to access the Value property of this instance.</p>
  
  <pre><code>Line 61:         // Load the log4net thread with additional properties if they are available
  Line 62:         protected internal void AddExtendedThreadInfo() {
  Line 63:             if (_shellSettings.Value != null) {
  Line 64:                 ThreadContext.Properties["Tenant"] = _shellSettings.Value.Name;
  Line 65:             }
  </code></pre>