How to determine what is causing catastrophic error - vba

Question

I am getting catastrophic error at certain sequence on listbox form selection...
how can I determine what exactly is causing catastrophic error? The error is repeatable from my file.
On bellow code I put msgbox "a" and error doesn't appear any more... If I remove that it will apear again. Also it appears only right after I run the excel file and open forms and select item on that listbox.
Also the code is around 4000 lines and 150000 characters for this specific form. With other classes it's over 10000 lines and over 300000 characters.
Private Sub ListBox3_Change()
Dim partf As Variant, ctype As String
ReDim fncleft(4)
ReDim fncright(4)
Dim i As Integer, h As Integer
For i = 0 To Me.ListBox3.ListCount - 1
If Me.ListBox3.Selected(i) = True Then
With bomfix.ExcelTables(Me.ComboBox_Tables2.Value).settings
If Me.ListBox3.List(i, 1) <> vbNullString Then
Me.CheckBox_SQLltrim.Enabled = True
Me.CheckBox_SQLrtrim.Enabled = True
Me.CheckBox_SQLtrim.Enabled = True
Me.CheckBox_SQLlower.Enabled = True
Me.CheckBox_SQLupper.Enabled = True
Me.CommandButtonSQLreplace.Enabled = True
Me.Frame9.Visible = True
Me.TextBox_ConstraintType.Visible = True
Me.CommandButton8.Visible = True
Me.Label99.Visible = True
Me.Label100.Visible = True
Me.TextBox_ConstrTableName.Visible = True
Me.TextBox_ConstrColumnName.Visible = True
If .TableExists(Me.ListBox3.List(i, 0)) = True Then
If .Table(Me.ListBox3.List(i, 0)).ColumnExists(Me.ListBox3.List(i, 1)) = True Then
Me.ComboBox_PartTable.List = .Tables
Me.ComboBox_PartTable.AddItem vbNullString, 0
With .Table(Me.ListBox3.List(i, 0))
Me.CheckBox_FullJoinTable.Enabled = True
Me.CheckBox_FullJoinTable.Value = .FullJoin
With .column(Me.ListBox3.List(i, 1))
Me.TextBox_ExportName.Value = .Value
Me.CheckBox_ColumnHidden.Value = .Hidden
Me.CheckBox_ColumnEnabled.Value = .Active
Me.TextBox_ConstraintType.Value = .ConstraintType
Me.TextBox_ConstrTableName.Value = .ConstraintTable
Me.TextBox_ConstrColumnName.Value = .ConstraintColumn
Me.CheckBox_SQLltrim.Value = .SQLltrim
Me.CheckBox_SQLrtrim.Value = .SQLrtrim
Me.CheckBox_SQLtrim.Value = .SQLtrim
Me.CheckBox_SQLlower.Value = .SQLlower
Me.CheckBox_SQLupper.Value = .SQLupper
MsgBox "b"
partf = .PartitionFilter
If Not UBound(partf) < 0 Then
Me.TextBox_PartResults.Value = partf(0)
If bomfix.ExcelTables(Me.ComboBox_Tables2.Value).settings.TableExists(partf(1)) = True Then
Me.ComboBox_PartTable.Value = partf(1)
Me.ComboBox_PartColumn.List = bomfix.ExcelTables(Me.ComboBox_Tables2.Value).settings.Table(Me.ComboBox_PartTable.Value).Columns
Me.ComboBox_PartColumn.AddItem vbNullString, 0
If bomfix.ExcelTables(Me.ComboBox_Tables2.Value).settings.Table(partf(1)).ColumnExists(partf(2)) = True Then
Me.ComboBox_PartColumn.Value = partf(2)
Me.ComboBox_PartOrderBy.Value = partf(3)
End If
End If
Else
Me.TextBox_PartResults.Value = vbNullString
Me.ComboBox_PartTable.Value = vbNullString
Me.ComboBox_PartColumn.Value = vbNullString
Me.ComboBox_PartOrderBy.Value = vbNullString
End If
Me.TextBox_FuncLeftCol.Value = Me.ListBox3.List(i, 0) & "." & Me.ListBox3.List(i, 1)
Me.ComboBox_FuncRightVal.Value = Me.ComboBox_FuncRightVal.List(0)
' add filters Array(and_or, Comparator, tableright, columnright, FunctionRight, FunctionLeft)
Me.ListBox4.Clear
For h = 1 To .FilterSet.Count
Me.ListBox4.AddItem
Me.ListBox4.List(Me.ListBox4.ListCount - 1, 0) = .FilterSet(h)(0) ' and_or
Me.ListBox4.List(Me.ListBox4.ListCount - 1, 1) = Join(.FilterSet(h)(5), "|") ' function left
Me.ListBox4.List(Me.ListBox4.ListCount - 1, 2) = .FilterSet(h)(1) ' comparator
Me.ListBox4.List(Me.ListBox4.ListCount - 1, 3) = .FilterSet(h)(2) ' table right
Me.ListBox4.List(Me.ListBox4.ListCount - 1, 4) = .FilterSet(h)(3) ' column right
Me.ListBox4.List(Me.ListBox4.ListCount - 1, 5) = Join(.FilterSet(h)(4), "|") ' function right
Next
End With
End With
End If
End If
ElseIf Me.ListBox3.List(i, 2) <> vbNullString Then
If .Aggregates.Exists(Me.ListBox3.List(i, 0)) = True Then
With .Aggregates(Me.ListBox3.List(i, 0))(1)
Me.CheckBox_SQLltrim.Enabled = False
Me.CheckBox_SQLrtrim.Enabled = False
Me.CheckBox_SQLtrim.Enabled = False
Me.CheckBox_SQLlower.Enabled = False
Me.CheckBox_SQLupper.Enabled = False
Me.CommandButtonSQLreplace.Enabled = False
Me.CheckBox_FullJoinTable.Enabled = False
Me.Frame9.Visible = False
Me.TextBox_ConstraintType.Visible = False
Me.CommandButton8.Visible = False
Me.Label99.Visible = False
Me.Label100.Visible = False
Me.TextBox_ConstrTableName.Visible = False
Me.TextBox_ConstrColumnName.Visible = False
Me.TextBox_ExportName.Value = .Value
Me.CheckBox_ColumnHidden.Value = .Hidden
Me.CheckBox_ColumnEnabled.Value = .Active
Me.TextBox_ConstraintType.Value = .ConstraintType
Me.TextBox_ConstrTableName.Value = .ConstraintTable
Me.TextBox_ConstrColumnName.Value = .ConstraintColumn
Me.TextBox_FuncLeftCol.Value = "aggregate"
Me.ComboBox_FuncRightVal.Value = Me.ComboBox_FuncRightVal.List(0)
' add filters Array(and_or, Comparator, tableright, columnright, FunctionRight, FunctionLeft)
Me.ListBox4.Clear
For h = 1 To .FilterSet.Count
Me.ListBox4.AddItem
Me.ListBox4.List(Me.ListBox4.ListCount - 1, 0) = .FilterSet(h)(0)
Me.ListBox4.List(Me.ListBox4.ListCount - 1, 1) = Join(.FilterSet(h)(5), "|")
Me.ListBox4.List(Me.ListBox4.ListCount - 1, 2) = .FilterSet(h)(1)
Me.ListBox4.List(Me.ListBox4.ListCount - 1, 3) = .FilterSet(h)(2)
Me.ListBox4.List(Me.ListBox4.ListCount - 1, 4) = .FilterSet(h)(3)
Me.ListBox4.List(Me.ListBox4.ListCount - 1, 5) = Join(.FilterSet(h)(4), "|")
Next
End With
End If
End If
End With
Exit For
End If
Next
Me.ComboBox_FuncTypeRight.Value = Me.ComboBox_FuncTypeRight.List(0)
Me.ComboBox_FuncTypeLeft.Value = Me.ComboBox_FuncTypeLeft.List(0)
Call ComboBox_FuncComp_Change
End Sub