VBA macro only works once.

Hey guys,

So I have code written to merge the data from multiple spreadsheets into one. It works fine when I first write the program and press play, I can even press play multiple times and it will append the data to the bottom of the spreadsheet. However, if I save it and close it (with or without hitting play) and try to run the program once I open it I get an error.
VBA Error.jpg
Is there something I did wrong or am missing? Any help would be most appreciated.

Here is a copy of the code that I used.
'Finding files in folder

Sub LoopThroughDirectory()
    Dim MyFile As String
    Dim erow
    MyFile = Dir("C:\Basic Data Transfer\")
'Making sure file has data
    Do While Len(MyFile) > 0
'Ignoring File in folder
    If MyFile = "zmaster.xlsm" Then
    Exit Sub
    End If
'Open the files in the folder
    Workbooks.Open (MyFile)
'To copy specific cells from files
    Range("A2:A3:D2:D3").Copy
'Close the files
    ActiveWorkbook.Close
'Finding first empty row in master spreadsheet
    erow = Sheet1.Cells(Rows.Count, 1).End(xlUp).Offset(1, 0).Row
'Paste the data onto active sheet, on blank cells just determined
    ActiveSheet.Paste Destination:=Worksheets("sheet1").Range(Cells(erow, 1), Cells(erow, 4))
'Repeating for the next file
    MyFile = Dir
    Loop
    
End Sub