Stand-alone PDM app - AddInSrv.exe has many processes open

I created a stand-alone application that searches my PDM vault and opens a PDF.  The user inputs the part number, the app searches for a PDF with that part number, then opens it.  It appears that the 'file.GetFileCopy' method launches the AddInSrv.exe process.  The issue I am having is this process stays open and creates a new process when the user opens for another PDF.    After opening 10 PDFs, there are (10) or more AddInSrv.exe processes open, each using 10MB of memory.  I thought that setting the objects File and Vault to nothing would solve this, but it does not.  I thought about adding code that will simply kill this process after the PDF is open, but I am not sure if this would cause an adverse effects.

Any ideas what may be causing this and how I can unload this process after file is opened?

CODE:

    Private Sub ListBox1_DoubleClick(sender As Object, e As EventArgs) Handles ListBox1.DoubleClick

        Dim vault As New EdmVault5

        vault.LoginAuto("MYVAULT", 0)

        Dim fullPath = ListBox1.SelectedItem.ToString()

        Dim File As IEdmFile5 = Nothing

        Dim ParentFolder As IEdmFolder5 = Nothing

        File = vault.GetFileFromPath(fullPath, ParentFolder)

        File.GetFileCopy(0)

        'MsgBox(fullPath)

        System.Diagnostics.Process.Start(fullPath)

        File = Nothing

        vault = Nothing

    End Sub

SolidworksApi/macros