C# Process: The system cannot find the file specified

Question

Please excuse me if I am asking a dumb question as I am a novice programmer on C#.

I am seeing different behavior of Process on Windows Server 2008 and 2003.

Below is my code snippet:

            Process job = new Process();
            job.StartInfo.FileName = global.m_sShell;
            job.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
            job.StartInfo.Arguments = EXE;
            job.StartInfo.UseShellExecute = false;
            job.StartInfo.RedirectStandardError = true;
            job.StartInfo.RedirectStandardOutput = true;
            job.StartInfo.RedirectStandardInput = false;
            shellScriptRetCode = job.Start();

"global.m_sShell" is a string that contains a system path like "E:\abc\ksh.exe". [This string has been fetched from a registry key]

The process starts well on Windows Server 2008 but on Windows Server 2003 (32-bit) I am getting error

             The system cannot find the file specified

I have checked the file manually and it exists on the server. Now, if I hard code the filename like:

            job.StartInfo.FileName = @"E:\abc\ksh.exe";

it works fine.

The thing is that I have to fetch the path key from registry and use that to launch the process.

Please provide me with your expert comments.

Thanks!