Copy paste error, object invoked disconnected from its client

[EileenJohn]

My code:
'Force the explicit declaration of variables
Option Explicit
Dim TimeToRun

Sub UpdateRecord()

'Declare the variables
Dim MyPath As String
Dim MyFile As String
Dim LatestFile As String
Dim LatestDate As Date
Dim LMD As Date

'Specify the path to the folder
MyPath = "C:\Users\Desktop\RECORD"

'Make sure that the path ends in a backslash
If Right(MyPath, 1) <> "" Then MyPath = MyPath & ""

'Get the first Excel file from the folder
MyFile = Dir(MyPath & "*.csv", vbNormal)

'If no files were found, exit the sub
If Len(MyFile) = 0 Then
MsgBox "No files were found...", vbExclamation
Exit Sub
End If

'Loop through each Excel file in the folder
Do While Len(MyFile) > 0

'Assign the date/time of the current file to a variable
LMD = FileDateTime(MyPath & MyFile)

'If the date/time of the current file is greater than the latest
'recorded date, assign its filename and date/time to variables
If LMD > LatestDate Then
LatestFile = MyFile
LatestDate = LMD
End If

'Get the next Excel file from the folder
MyFile = Dir

Loop

'Open the latest file
Workbooks.Open MyPath & LatestFile
Dim lastrow As Long, lastcolumn As Long, erow As Long

'Copy
lastrow = ActiveSheet.Cells(Rows.Count, 1).End(xlUp).Row
lastcolumn = ActiveSheet.Cells(1, Columns.Count).End(xlToLeft).Column
Range(Cells(2, 1), Cells(lastrow, lastcolumn)).Copy
Application.DisplayAlerts = False
ActiveWorkbook.Close


'paste
erow = Sheet1.Cells(Rows.Count, 1).End(xlUp).Offset(1, 0).Row
lastcolumn = ActiveSheet.Cells(1, Columns.Count).End(xlToLeft).Column
ActiveSheet.Paste Destination:=Worksheets("sheet1").Range(Cells(erow, 1), Cells(erow, lastcolumn)) **this line have problem
Cells.Select
Range("Q10").Activate
ActiveSheet.UsedRange.RemoveDuplicates Columns:=Array(1, 2, 3, 4, 5, 6 _
, 7, 8, 9, 10, 11, 12, 13, 14, 15), Header:=xlYes

Application.DisplayAlerts = True
End Sub

The code above works fine before. However, when I try to run the code today, it give me an error "excel cannot paste the data" something like "object invoked disconnected from its client"
But when i rename sheet1. It works!! -> ActiveSheet.Paste Destination:=Worksheets("sheet1").Range(Cells(erow, 1), Cells(erow, lastcolumn))

Is there any part of the coding i should change? To prevent the problem recurring?