Строковые функции. Заменить все пустые строки на С - VB

Option Explicit
 
Private Sub Form_Load()
    Dim z As String, fnum As Integer, C As String
    C = "FFFFF"
    fnum = FreeFile
    Open "D:\Temp\Script3.txt" For Binary As fnum
    z = Space(LOF(fnum))
    Get fnum, , z
    Do While InStr(1, z, vbNewLine & vbNewLine)
    z = Replace(z, vbNewLine & vbNewLine, vbNewLine & C & vbNewLine)
    Loop
    Put fnum, 1, z
    Close fnum
End Sub