Macro has stopped working - vba

Question

My wife has a spread sheet at work that has stopped working. You input the data into one tab on a nice easy to use sheet, then press a button and the data is transferred to a table on another sheet. the input tab is called "NCR Report" and the table tab is called "PM2" below is the macro. Any idea why it has stopped working?
Sub Button111_Click()
Dim a As Date
Dim Counter As Integer
Dim Filled As Boolean
Dim ParamOut As String
Dim i As Integer
Dim Reels As String
MsgBox ("Wait...")
'Identify 1st empty row
Counter = 3
While Filled = False
Counter = Counter + 1
a = Worksheets("PM 2").Cells(Counter, 1).Value
If a = 0 Then
Filled = True
Else: Filled = False
End If
Wend
'Shift
Worksheets("PM2").Cells(Counter, 2).Value = Worksheets("NCR Report").Cells(2, 7).Value
'Production date
Worksheets("PM2").Cells(Counter, 1).Value = Worksheets("NCR Report").Cells(3, 7).Value
'Article number
Worksheets("PM2").Cells(Counter, 4).Value = Worksheets("NCR Report").Cells(4, 7).Value
'Total weight
Worksheets("PM2").Cells(Counter, 5).Value = Worksheets("NCR Report").Cells(16, 8).Value
'Parameter out, build the string
ParamOut = ""
For i = 21 To 24
If Worksheets("NCR Report").Cells(i, 2).Text <> "" Then
ParamOut = ParamOut & " " & Worksheets("NCR Report").Cells(i, 2).Text & " " & Worksheets("NCR Report").Cells(i, 5).Text & " " & Worksheets("NCR Report").Cells(i, 9).Text & " " & Worksheets("NCR Report").Cells(i, 10).Text
End If
Next i
Worksheets("PM2").Cells(Counter, 6).Value = ParamOut
'Adjustements
Worksheets("PM2").Cells(Counter, 7).Value = Worksheets("NCR Report").Cells(29, 2).Value
'Reel number
Reels = ""
Reels = Worksheets("NCR Report").Cells(10, 2).Text
For i = 11 To 15
If Worksheets("NCR Report").Cells(i, 2).Value = 0 Then
Else: Reels = Reels & " / " & Worksheets("NCR Report").Cells(i, 2).Text
End If
Next i
Worksheets("PM2").Cells(Counter, 3).Value = Reels
MsgBox ("NCR has been successfully added to the spreadsheet." & vbCrLf & "Don't forget to save this file before quitting and also to block the reels on PLAIN.")
End Sub

Answer 1

You've got inconsistent references to the sheet name.
In one case its:
a = Worksheets("PM 2").Cells(Counter, 1).Value
And later its:
Worksheets("PM2").Cells(Counter, 2).Value = Worksheets("NCR Report").Cells(2, 7).Value
The code needs to match the actual name of the worksheet, either with or without the space