Unable to start debugging on the web server.

Click Start, point to Programs, point to Administrative Tools, and then click Domain Controller Security Policy.

Click Security Settings.

Click Local Policies, and then click User Rights Assignment.
In the right pane, double-click Impersonate a client after authentication.

In the Security Policy Setting window, click Define these policy settings.
Click Add, and then click Browse.

In the Select Users or Groups window, select the IWAM account name, click Add, and then click OK.
Click OK two times.

To enforce an update of the computer policy, type the following command at a command prompt, and then press ENTER:
secedit /refreshpolicy machine_policy /enforce

At the command prompt,
type iisreset, and then press ENTER.