I'm getting error in checking out and checking in any file. Any idea what am I doing wrong with this CheckOut functions?

Any file that I try to check-in or check-out fails. Error message is something like: "You don't have permission to perform this action."

I have enough permissions(Admin) and file is in correct checked in / out state.

Imports EPDM.Interop.epdm

Public Class Form1
    Dim filename As String = "Filename.SLDPRT"
    Dim VaultName As String = "VAULTNAME"
    Dim vault1 As IEdmVault20 = New EdmVault5()

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        LogIn(1)

        Dim searchresult As IEdmSearchResult5
        searchresult = Searchfile(filename)

        CheckOut(searchresult)
        CheckIn(searchresult)

    End Sub

    Function LogIn(autologin As Integer)
        If Not vault1.IsLoggedIn Then
            vault1.LoginAuto(VaultName, Me.Handle.ToInt32())
        End If
        Return 1
    End Function

    Function Searchfile(filename2 As String)
        Dim Search As IEdmSearch8
        Search = vault1.CreateUtility(EdmUtility.EdmUtil_Search)

        Search.FileName = filename
        Dim Result As IEdmSearchResult5
        Dim i As Integer = 0

        Result = Search.GetFirstResult
        Return Result
    End Function
    Function CheckOut(searchresults As IEdmSearchResult5)
        Dim afile As IEdmFile16
        afile = vault1.GetFileFromPath(searchresults.Path)
        afile.LockFile(searchresults.ID, Me.Handle.ToInt32(), CInt(EdmLockFlag.EdmLock_Simple))

        Return 1
    End Function

    Function CheckIn(searchresults As IEdmSearchResult5)
        Dim afile As IEdmFile16
        afile = vault1.GetFileFromPath(searchresults.Path)
        afile.UnlockFile(searchresults.ID, Me.Handle.ToInt32(), CInt(EdmLockFlag.EdmLock_Simple))
        Return 1
    End Function

End Class