Setup IIS progrmically and set up virtual directory on win7.?

Thank you very much.
It would be greate help for me.
But I have some errors while excuting following codes.
public static bool AddVirtualDirectory(string siteName, string application, string virtualDirectoryPath, string physicalPath, string userName, string password)
{
try
{
if (string.IsNullOrEmpty(siteName))
throw new ArgumentNullException("siteName", "AddVirtualDirectory: siteName is null or empty.");
if (string.IsNullOrEmpty(application))
throw new ArgumentNullException("application", "AddVirtualDirectory: application is null or empty.");
if (string.IsNullOrEmpty(virtualDirectoryPath))
throw new ArgumentNullException("virtualDirectoryPath", "AddVirtualDirectory: virtualDirectoryPath is null or empty.");
if (string.IsNullOrEmpty(physicalPath))
throw new ArgumentNullException("physicalPath", "AddVirtualDirectory: physicalPath is null or empty.");
using (ServerManager mgr = new ServerManager())
{
Site site = mgr.Sites[siteName];
if (site != null)
{
Application app = site.Applications[application];
if (app != null)
{
VirtualDirectory vDir = app.VirtualDirectories[virtualDirectoryPath];
if (vDir != null)
{
throw new Exception("Virtual Directory: " + virtualDirectoryPath + " already exists.");
}
else
{
vDir = app.VirtualDirectories.CreateElement();
vDir.Path = virtualDirectoryPath;
vDir.PhysicalPath = physicalPath;
if (!string.IsNullOrEmpty(userName))
{
if (string.IsNullOrEmpty(password))
throw new Exception("Invalid Virtual Directory User Account Password.");
else
{
vDir.UserName = userName;
vDir.Password = password;
}
}
app.VirtualDirectories.Add(vDir);
}
mgr.CommitChanges();
return true;
}
else
throw new Exception("Application: " + application + " does not exist.");
}
else
throw new Exception("Site: " + siteName + " does not exist.");
}
}
catch (Exception ex)
{
throw new Exception(ex.Message, ex);
}
}
Thanks again.