Getting No application is associated with the specified file for this operation while executing AutoIt scripts from vb.net

I have installed AutoIt on my machine. Its working ok on one machine but same configuration and code is not working on other. Any idea what I am missing?

Following error

 Could not start process Z:\test\AutoItScripts\test.au3  
 No application is associated with the specified file for this operation

Also autoit script successfully exe开发者_JAVA百科cutes from command line. Its just getting this error while using the following code to execute

        objProcess = New System.Diagnostics.Process()
        objProcess.StartInfo.Verb = "runas"
        objProcess.StartInfo.Arguments = Argument
        objProcess.StartInfo.FileName = ProcessPath
        objProcess.Start()
        'Wait until it's finished
        objProcess.WaitForExit()
        'Exitcode as String
        Console.WriteLine(objProcess.ExitCode.ToString())
        objProcess.Close()

Because AutoIt3 scripts are not themselves executable, you will need to be using shellexecute.

p.UseShellExecute = true;

Process compiler = new Process();
compiler.StartInfo.FileName = sExeName;
compiler.StartInfo.Arguments = sParameters;
compiler.StartInfo.UseShellExecute = false;
compiler.StartInfo.RedirectStandardOutput = true;
compiler.Start();
Console.WriteLine(compiler.StandardOutput.ReadToEnd());