Type mismatch error

[katlong]

Can anyone help me with the bold code that is a type mismatch below?

Sub Promise_Date_Change_Detector()
Application.ScreenUpdating = True
Dim WB As Workbook, WS As Worksheet
Dim c As Variant
Set fso = CreateObject("Scripting.FileSystemObject")
Set fldr = fso.GetFolder("U:\Public\All Customer Reports\All Customers Report 2018")
'Label Column Headers , "PO#", "Sales Order", "Line #", "Promise Date","file date"
Cells(5, 1).Value = "PO#"
Cells(5, 2).Value = "Sales Order"
Cells(5, 3).Value = "Line #"
Cells(5, 4).Value = "Promise Date"
'Build Input Box to Inquire as to PO in Question
PurchaseOrder = InputBox("What PO would you like information for?", "PO#?")
'Find Order Date in Latest file
LFile = Worksheets(1).Cells(2, 6).Value
Workbooks.Open (LFile)
k = Worksheets(1).Cells(Rows.Count, 1).End(xlUp).Row
For l = 2 To k
If Worksheets(1).Cells(l, 2).Value = PurchaseOrder Then
n = Worksheets(1).Cells(l, 14).Value
End If
Next l
o = n + 2
o = Format(o, "mm-dd-yyyy")
StrtFile = Application.WorksheetFunction.Concat(fldr, "", o, "am")
'Loop through all the files in the customers report folder and pull out the po info
x = ThisWorkbook.Sheets("Sheet1").Cells(Rows.Count, 1).End(xlUp).Row + 1
For c = StrtFile To LFile
Application.DisplayAlerts = False
If fso.GetExtensionName(wbFile.Name) = "xls" Then
Set WB = Workbooks.Open(wbFile.Path)
Set WS = Worksheets(1)
wsLR = WS.Cells(Rows.Count, 1).End(xlUp).Row

For Y = 2 To wsLR
If WS.Cells(Y, 2).Value = PurchaseOrder Then
Z = 6
WS.Cells(Y, 2).Copy Destination:=ThisWorkbook.Worksheets(1).Cells(Z, 1)
WS.Cells(Y, 3).Copy Destination:=ThisWorkbook.Worksheets(1).Cells(Z, 2)
WS.Cells(Y, 4).Copy Destination:=ThisWorkbook.Worksheets(1).Cells(Z, 3)
WS.Cells(Y, 21).Copy Destination:=ThisWorkbook.Worksheets(1).Cells(Z, 4)
Z = Z + 1
End If
x = x + 1
Next Y
End If
WB.Close (wbFile.Path)
Application.DisplayAlerts = True
Next c


'concatenate po and promise date
'remove duplicate rows
Application.ScreenUpdating = True
End Sub

 

[JonXL]

What is StrtFile?

 

[katlong]

What is StrtFile?

StrtFile is the file in the folder I'm starting the loop with - it's variable based on date. I'm not starting at the beginning of the files in the folder. (there are nearly 800 files in the folder, so we want to loop through just the ones we need so I'm starting at date + 2 days from the date on the PO issued. Thanks for looking at this.

I'm thinking I may have to count how many files first? Thanks for any help