Please help me to debug this VB code

Public wb As Workbook
Public ErrDesc() As String

'global workbook variable for new workbook
Public Sub DocumentError()

Dim Rng As Excel.Range
Dim ln_count As Long
Dim RowNum As Long
Dim response As Variant
Dim RowNum_Arr(0 To 5000) As String


Application.Cursor = xlWait
Application.DisplayAlerts = False

Set wb = Workbooks.Add
Application.ScreenUpdating = False

Sheets("Sheet2").Select
Sheets("Sheet2").Delete

Sheets("Sheet3").Select
Sheets("Sheet3").Delete

Rows("1:1").RowHeight = 18

Range("A1").Value = "S.No."
Range("B1").Value = "Feed File Row Number"
Range("C1").Value = "Error Description"

Columns("A:A").ColumnWidth = 9
Columns("B:B").ColumnWidth = 20
Columns("C:C").ColumnWidth = 85

Rows("1:1").Select
With Selection.Font
.Name = "Times New Roman"
.Size = 10
.Strikethrough = False
.Superscript = False
.Subscript = False
...