Redgate ANTS Performance Profiler 6.3 gives error: Failed to connect to target process because an exception occurred, "Could not start IIS"

Just downloaded a 14 day trial of "ANTS Performance Profiler 6.3" to check performance on my web application. Here are my configuration settings after beginning a new session (via the File menu). I'm on Windows 7 and running IIS 7. This web application is using forms authentication. I just logged into the site, and to the page I specified in the "ASP.NET web application (URL)" field. What could cause this error?

I'm taking a wild guess, I need to give the profiler (user) permissions to my web application, yes? If so, what user can I use? Or do I need to change the application pool Identity user to something different?

Download URL:

http://www.red-gate.com/products/dotnet-development/ants-performance-profiler/

Settings:

Error (after clicking "Start Profiling" button):

Well, when I changed the application pool "Identity" user of my web application from ApplicationPoolIdentity to LocalSystem, it worked. I suppose I could have also changed the user in the service (Control Panel > Services > ANTS Performance Profiler 6 Service) to some other user and used that user.

But then I get another error. As Kip says in Napolean Dynamite, "I love technology."

Stack Trace in Details window:

Could not start w3wp as the specified user. Win32 error code: 87
RedGate.Profiler.Engine.Startup.IIS.IISException
stack trace: 
  at ..StartProfilingIIS(String , String )
  at RedGate.Profiler.Engine.Startup.IIS.IISStarter`1.StartProfilingIIS(String currentUserName, String subprocessVariableValue)
  at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs)
  at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg, Int32 methodPtr, Boolean fExecuteInContext)
rethrown at [0]: 
  at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
  at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
  at RedGate.Profiler.Engine.Startup.IIISActuator`1.StartProfilingIIS(String currentUserName, String subprocessVariableValue)

After messing around with the error above for a bit, I tried unchecking this option, and it launched my default browser (which appears to be IE 9). Seems to be working now.