Selecting the "front plane" in solidworks api

Guys I've been trying to select the "front plane" and draw a  sketch on it. When I execute the file,  the code gives me an error saying " object not set to reference".But its already declared as a boolean. Why is it still showing it as " not set to a reference"

Can you please help ?

Thanks a lot

public Class Rectangleform

    Dim swapp As New SldWorks

    Dim swmodel As IModelDoc2

    Dim plane As IModelDocExtension

    Dim sketch As ISketchManager

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

        swapp.Visible = True

        swapp.NewPart()

        swapp.IActiveDoc.Visible = True

        Selectfrontplane()

        sketch.InsertSketch(True)

    End Sub

    Public Function Selectfrontplane() As Boolean

        Dim Name As String = "Front Plane"

        Dim Type As String = "PLANE"

        Dim X As Double = 0

        Dim Y As Double = 0

        Dim Z As Double = 0

        Dim Append As Boolean = False

        Dim Mark As Integer = 0

        Dim Callout As Callout = Nothing

        Dim SelectOption As Integer = 0

        Dim value As Boolean = True

        value = plane.SelectByID2(Name, Type, X, Y, Z, False, 0, Callout, SelectOption)

        Return value

    End Function

End Class

SolidworksApi macros