Error running a command line .exe from asp.net - asp.net

Question

I have a command line program which runs fine from the DOS window interactively. When I try to execute the same command and arguments from within an asp.net app, it fails. The web app has Script & Execute permissions. For testing purposes, I gave full control permissions to the Everyone group for the whole web app folder and for the folder containing the .exe file (resides in Program Files). The web app is using Windows integrated security (no anonymous) so it should use my credentials and I am an admin. Running in WIndows XP.
The code below runs the command. The filename and arguments look good. However the p.ExitCode =1 instead of 0. How do I troubleshoot and find out why the process is failing? I looked at the process in the debugger and I see some 'System.InvalidOperationException' exceptions but that doesn't tell me much. Why InvalidOperationException?
Process p = new Process();
p.StartInfo.FileName = filename;
p.StartInfo.Arguments = arguments;
p.StartInfo.CreateNoWindow = true;
p.StartInfo.UseShellExecute = true;
p.StartInfo.RedirectStandardOutput = false;
p.StartInfo.RedirectStandardError = false;
p.Start();
p.WaitForExit();
if (0 != p.ExitCode)
{
ApplicationException ex =
new ApplicationException(string.Format("\"{0} {1}\" returned ({2})", filename, arguments, p.ExitCode));
throw ex;
}

Answer 1

There's a variety of things an app can do which would cause problems when ran by another app unfortunately, with no further info there's simply too many options.
You'll probably have to redirect standard output and/or standard error to find out what's going wrong (Or if the command-line program is .NET you'll likely have errors in your windows Event Log).
For a simple test you could do something as simple as:
p.StartInfo.RedirectStandardError = true;
p.Start();
p.WaitForExit();
string err = p.StandardError.ReadToEnd();
Note that you'll need a more complicated threaded solution for a real build, as if the console app writes too much data to standard error it'll fill the buffer and hang. I can help you out with a more robust solution for console output if you need it, but this will likely get you your debug info.

Answer 2

The web app is using Windows
integrated security (no anonymous) so
it should use my credentials and I am
an admin
No, that's not correct. The worker process still runs under ASPNET for Windows XP default settings, unless you enable ASP.NET impersonation.