xlsm file error upon sending through email - excel

Question

I am a newbie vba coder here.
I have created an .xlsm with userform. Everything works fine in my computer, but when I send the file over via email, the recipient will encounter the following issues when opening the file:
I added an event handler on Workbook_Open to automatically open the userform. When the recipient open the file, it will receive this error and Debug button returns to this line:
When Submit button of the Userform is clicked, the data is supposed to be transferred to 'ThisWorkbook' but instead it creates a new file (i guess the previous version) and paste the data there.
Can anyone help me to figure out what went wrong with my file? Thank you.
Below is my code:
Inside Workbook Event Handler:
Sub Workbook_Open()
RunForm
End Sub
Module1:
Option Explicit
Option Base 1
Sub PopulateComboBox()
Dim PaymentTerms() As String, PaymentFreq() As String, PaymentTermsAlt() As String
Dim i As Integer, j As Integer, m As Integer, n As Integer, o As Integer
j = WorksheetFunction.CountA(Sheets("Populate").Columns("A:A"))
n = WorksheetFunction.CountA(Sheets("Populate").Columns("B:B"))
ReDim PaymentTerms(j - 1) As String
ReDim PaymentFreq(n - 1) As String
ReDim PaymentTermsAlt(j - 1) As String
For i = 1 To j - 1
PaymentTerms(i) = ThisWorkbook.Sheets("Populate").Range("A2:A" & (j - 1)).Cells(i, 1)
UserForm1.ComboTerms.AddItem PaymentTerms(i)
Next i
For m = 1 To n - 1
PaymentFreq(m) = ThisWorkbook.Sheets("Populate").Range("B2:B" & (n - 1)).Cells(m, 1)
UserForm1.ComboFreq.AddItem PaymentFreq(m)
Next m
For o = 1 To j - 1
PaymentTermsAlt(o) = ThisWorkbook.Sheets("Populate").Range("A2:A" & (j - 1)).Cells(o, 1)
UserForm1.ComboTermsAlt.AddItem PaymentTermsAlt(o)
Next o
UserForm1.ComboTerms.Text = PaymentTerms(1)
UserForm1.ComboFreq.Text = PaymentFreq(1)
UserForm1.ComboTermsAlt.Text = PaymentTermsAlt(1)
End Sub
Sub RunForm()
ThisWorkbook.Sheets("Printout").Activate
UserForm1.Show
End Sub
Inside Userform:
Option Explicit
Sub CommandButton1_Click()
Application.ScreenUpdating = False
If Not IsNumeric(BasePay) Or Not IsNumeric(Interest) Then
MsgBox ("Please Enter Numeric Value for Base Pay or Interest Rate")
Exit Sub
End If
If BasePay < 0 Or Interest < 0 Then
MsgBox ("Base Pay or Interest cannot be negative value")
Exit Sub
End If
ThisWorkbook.Sheets("Printout").Range("A1") = "Prepared For " & ClientName
ThisWorkbook.Sheets("Printout").Range("O1").Value = BasePay.Text
ThisWorkbook.Sheets("Printout").Range("S2").Value = Interest.Text / 100
ThisWorkbook.Sheets("Printout").Range("L3").Value = ComboTerms.Text
ThisWorkbook.Sheets("Printout").Range("O3").Value = ComboFreq.Text
ThisWorkbook.Sheets("Printout").Range("Q2").Value = ComboTermsAlt.Text
If NewCar Then
ThisWorkbook.Sheets("Printout").Range("U2").Value = "New"
Else
ThisWorkbook.Sheets("Printout").Range("U2").Value = "Used"
End If
'----- Transfer Add-On Items to Printout Sheet ---------
Dim i As Integer
Dim j As Integer
Dim k As Integer
k = 6
For i = 1 To 9
ThisWorkbook.Sheets("Printout").Cells(k, 1).MergeArea.ClearContents
k = k + 2
Next
k = 6
For i = 10 To 18
ThisWorkbook.Sheets("Printout").Cells(k, 5).MergeArea.ClearContents
k = k + 2
Next
k = 6
For i = 19 To 27
ThisWorkbook.Sheets("Printout").Cells(k, 9).MergeArea.ClearContents
k = k + 2
Next
k = 6
For i = 28 To 36
ThisWorkbook.Sheets("Printout").Cells(k, 13).MergeArea.ClearContents
k = k + 2
Next
'---- Category 1 ------
i = 6
For j = 1 To 9
If UserForm1.Controls("Checkbox" & j).Value = True Then
ThisWorkbook.Sheets("Printout").Range("A" & i).Value = Me.Controls("Checkbox" & j).Caption
i = i + 2
Else
ThisWorkbook.Sheets("Printout").Range("A" & i).Value = ""
End If
Next j
'---- Category 2 ------
i = 6
For j = 10 To 18
If UserForm1.Controls("Checkbox" & j).Value = True Then
ThisWorkbook.Sheets("Printout").Range("E" & i).Value = Me.Controls("Checkbox" & j).Caption
i = i + 2
Else
ThisWorkbook.Sheets("Printout").Range("E" & i).Value = ""
End If
Next j
'---- Category 3 ------
i = 6
For j = 19 To 27
If UserForm1.Controls("Checkbox" & j).Value = True Then
ThisWorkbook.Sheets("Printout").Range("I" & i).Value = Me.Controls("Checkbox" & j).Caption
i = i + 2
Else
ThisWorkbook.Sheets("Printout").Range("I" & i).Value = ""
End If
Next j
'---- Category 4 ------
i = 6
For j = 28 To 36
If UserForm1.Controls("Checkbox" & j).Value = True Then
ThisWorkbook.Sheets("Printout").Range("M" & i).Value = Me.Controls("Checkbox" & j).Caption
i = i + 2
Else
ThisWorkbook.Sheets("Printout").Range("M" & i).Value = ""
End If
Next j
UserForm1.Hide
End Sub
Sub CommandButton2_Click()
Unload UserForm1
UserForm1.Show
End Sub
Sub CommandButton3_Click()
Unload UserForm1
End Sub
Sub NewCar_Click()
Dim LastRow As Integer
Dim i As Integer
Dim j As Integer
LastRow = WorksheetFunction.CountA(Sheets("Populate").Columns("D:D"))
'---- Count No of Checkbox
Dim Ctrl As MSForms.Control
Dim n As Integer
Dim cbcount As Long
For n = 0 To Me.Controls.Count - 1
If Left(UserForm1.Controls(n).Name, 8) = "CheckBox" Then
cbcount = cbcount + 1
End If
Next n
i = 2 '--- Preset counter i
For j = 1 To cbcount
UserForm1.Controls("Checkbox" & j).Caption = ThisWorkbook.Sheets("Populate").Cells(i, 4).Value
i = i + 1
If i > LastRow And i < (cbcount / 4) Then
UserForm1.Controls("Checkbox" & j).Caption = ""
End If
If i > LastRow And i > (cbcount / 4 + 1) Then
i = 2
End If
Next j
End Sub
Sub UsedCar_Click()
Dim LastRow As Integer
Dim i As Integer
Dim j As Integer
LastRow = WorksheetFunction.CountA(Sheets("Populate").Columns("D:D"))
'---- Count No of Checkbox
Dim Ctrl As MSForms.Control
Dim n As Integer
Dim cbcount As Long
For n = 0 To Me.Controls.Count - 1
If Left(Me.Controls(n).Name, 8) = "CheckBox" Then
cbcount = cbcount + 1
End If
Next n
i = 2 '--- Preset counter i
For j = 1 To cbcount
UserForm1.Controls("Checkbox" & j).Caption = ThisWorkbook.Sheets("Populate").Cells(i, 8).Value
i = i + 1
If i > LastRow And i < (cbcount / 4) Then
UserForm1.Controls("Checkbox" & j).Caption = ""
End If
If i > LastRow And i > (cbcount / 4 + 1) Then
i = 2
End If
Next j
End Sub
Sub UserForm_Initialize()
Call PopulateComboBox
'----- Rename Frame Boxes Caption
Dim k As Integer, nc As Integer
nc = 1
For k = 2 To 5
Me.Controls("Frame" & k).Caption = ThisWorkbook.Sheets("Printout").Cells(5, nc)
nc = nc + 4
Next k
'--------------------------------------------------
Dim LastRow As Integer
Dim i As Integer
Dim j As Integer
LastRow = WorksheetFunction.CountA(ThisWorkbook.Sheets("Populate").Columns("D:D"))
'---- Count No of Checkbox
Dim Ctrl As MSForms.Control
Dim n As Integer
Dim cbcount As Long
For n = 0 To Me.Controls.Count - 1
If Left(Me.Controls(n).Name, 8) = "CheckBox" Then
cbcount = cbcount + 1
End If
Next n
i = 2 '--- Preset counter i
For j = 1 To cbcount
UserForm1.Controls("Checkbox" & j).Caption = ThisWorkbook.Sheets("Populate").Cells(i, 4).Value
i = i + 1
If i > LastRow And i < (cbcount / 4) Then
UserForm1.Controls("Checkbox" & j).Caption = ""
End If
If i > LastRow And i > (cbcount / 4 + 1) Then
i = 2
End If
Next j
End Sub