Error starting process as another user

[Dominic]

Every thing work fine when I am not starting process as another user.

When I am starting process as another user, the authentication is
working (I can see it in my workstation security log), but I always
got the error: System.ComponentModel.Win32Exception "invalid
descriptor" at line 20

any idea?
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01 Dim command As New System.Diagnostics.ProcessStartInfo("C:
\Travail\Pcounter\account.exe")
02 Dim crptPassword As New System.Security.SecureString
03 Dim execcmd As System.Diagnostics.Process
04 Dim resultat As System.IO.StreamReader
05
06 command.UserName = "user"
07 command.Domain = "domain"
08
09 For Each unChar As Char In "psw"
10 crptPassword.AppendChar(unChar)
11 Next
12
13 command.Password = crptPassword
14 command.Arguments = "viewbal " + txbCIP.Text
15 command.RedirectStandardOutput = True
16 command.WindowStyle = ProcessWindowStyle.Hidden
17 command.UseShellExecute = False
18 command.WorkingDirectory = "C:\Travail\Pcounter\"
19
20 execcmd = System.Diagnostics.Process.Start(command)
21 resultat = execcmd.StandardOutput
22 execcmd.WaitForExit(2000)
23 If execcmd.HasExited Then
24 lblResultat.Text = resultat.ReadToEnd
25 End If
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