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.Componen tModel.Win32Exc eption "invalid
descriptor" at line 20

any idea?
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01 Dim command As New System.Diagnost ics.ProcessStar tInfo("C:
\Travail\Pcount er\account.exe" )
02 Dim crptPassword As New System.Security .SecureString
03 Dim execcmd As System.Diagnost ics.Process
04 Dim resultat As System.IO.Strea mReader
05
06 command.UserNam e = "user"
07 command.Domain = "domain"
08
09 For Each unChar As Char In "psw"
10 crptPassword.Ap pendChar(unChar )
11 Next
12
13 command.Passwor d = crptPassword
14 command.Argumen ts = "viewbal " + txbCIP.Text
15 command.Redirec tStandardOutput = True
16 command.WindowS tyle = ProcessWindowSt yle.Hidden
17 command.UseShel lExecute = False
18 command.Working Directory = "C:\Travail\Pco unter\"
19
20 execcmd = System.Diagnost ics.Process.Sta rt(command)
21 resultat = execcmd.Standar dOutput
22 execcmd.WaitFor Exit(2000)
23 If execcmd.HasExit ed Then
24 lblResultat.Tex t = resultat.ReadTo End
25 End If
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