Compile error: variable not defined

New to VBA and just trying to make some edits to some existing code. I have basically copied a pre-existing form and module and changed names from "Appendix" to "Drawing" as I am trying to replicate what the piece of code already produces for a table of appendices, for my drawings. However, when I try and run the form I get Compile error: Variable not defined with lstDrawings highlighted.

Private Sub UserForm_Initialize()

Dim iNextDrawID  As Integer
Dim sNextDrawLet As String
Dim iChar       As Integer
Dim iDraw        As Integer
Dim sLet        As String
Dim sDesc       As String
Dim bBlankAfter As Boolean

iNextDrawID = 1
On Error Resume Next
iNextDrawID = ActiveDocument.CustomDocumentProperties("NextDrawingID").Value
On Error GoTo 0

sNextDrawLet = "A"
On Error Resume Next
sNextDrawLet = ActiveDocument.CustomDocumentProperties("NextDrawing").Value
On Error GoTo 0

If sNextDrawLet <> "A" Then

    For iChar = Asc("A") To Asc(sNextDrawLet) - 1

        For iDraw = 1 To iNextDrawID - 1

            sLet = ""
            On Error Resume Next
            sLet = ActiveDocument.CustomDocumentProperties("Drawing" & Format(iDraw, "00") & "_Let").Value
            On Error GoTo 0

            If sLet = Chr(iChar) Then

                sDesc = ""
                bBlankAfter = False
                On Error Resume Next
                sDesc = ActiveDocument.CustomDocumentProperties("Drawing" & Format(iDraw, "00") & "_Desc").Value
                bBlankAfter = CBool(ActiveDocument.CustomDocumentProperties("Drawing" & Format(iDraw, "00") & "_BlankPage").Value)
                On Error GoTo 0


                With lstDrawings
                    .AddItem sLet
                    .Column(1, .ListCount - 1) = sDesc
                    If bBlankAfter Then
                        .Column(2, .ListCount - 1) = "Yes"
                    Else
                        .Column(2, .ListCount - 1) = "No"
                    End If
                    .Column(4, .ListCount - 1) = iDraw
                End With





                Exit For

            End If

        Next

    Next

End If

End Sub

Is this something that should be defined in my global module which I am missing?

Any help is much appreciated.