Problem polega na tym ze o ile na komputerze działa, to już na dysku domenowym nie.
Process myProcess = new Process();
String Command = @"xcopy";
try
{
myProcess.StartInfo.UseShellExecute = false;
myProcess.StartInfo.FileName = Command;
myProcess.StartInfo.CreateNoWindow = false;
myProcess.StartInfo.UserName = "userName";
myProcess.StartInfo.Password = password;
myProcess.StartInfo.Domain = "domainName";
myProcess.StartInfo.ErrorDialog = true;
myProcess.StartInfo.LoadUserProfile = false;
myProcess.StartInfo.Arguments = @"d:\plik.ino W:\TEBD\Private";
myProcess.Start();
}