询问VB2010 启动外部程式有何限制呢?

Imports System.IO
Imports Ionic.Zip


Module Module1
    ' from QuickTime official website
    Private Const SAMPLE_FILE As String = "sample_mpeg4.mp4.zip"


    Public Sub Main()
        ' delete extracted file
        File.Delete("sample_mpeg4.mp4")


        ' use DotNetZip
        'ExtractByDotNetZip()


        ' use 7zip command line version
        'ExtractByCall()


        ' use Process.Start the wrong way
        ExtractWrong()


        ' pause
        Console.WriteLine("Finished.")
        Console.ReadKey()
    End Sub


    Private Sub ExtractByDotNetZip()
        Using zip As ZipFile = ZipFile.Read(SAMPLE_FILE)
            For Each entry As ZipEntry In zip
                Try
                    entry.Extract(ExtractExistingFileAction.OverwriteSilently)
                Catch ex As Exception
                    Console.WriteLine("Error {0}", ex.Message)
                End Try
            Next
        End Using
    End Sub


    Private Sub ExtractByCall()
        Dim _
            psi As _
                New ProcessStartInfo _
                With {.FileName = "7za.exe",
                .Arguments = String.Format("x {0} -aoa", SAMPLE_FILE)
                }
        Dim ret As Integer


        Using proc As Process = Process.Start(psi)
            proc.WaitForExit()
            ret = proc.ExitCode
        End Using


        If 0 = ret Then
            Console.WriteLine("OK!")
        Else
            Console.WriteLine("Error = {0}", ret)
        End If
    End Sub


    Private Sub ExtractWrong()
        Using _
            proc As Process =
                Process.Start(String.Format("7za.exe x {0} -aoa",
                                            SAMPLE_FILE))
            proc.WaitForExit()
        End Using
    End Sub
End Module