I am new to this level of VBA. I've read the forums and can't seem to figure out what is going wrong. I am getting the above error when I run a subroutine copying contents from one worbook and pasting it into a range in another. This only errors out the first time. If I run it again via a macro button, I do not get an error and the paste values work. Also, if I step through the Sub in VBA. I get no error. What am I missing? Thanks in advance for the help.

Following is the relevant code:

Private Sub Workbook_Open()

Set w = Workbooks

'Disable screen updating
Application.ScreenUpdating = False
Application.EnableEvents = False

'Open MasterLists file and copy contents
w.Open FileName:="\\[server]\shared\_Time Sheets\MasterLists.xlsm", UpdateLinks:=False, ReadOnly:=True, Password:="Pwd123"
ActiveWindow.Visible = False
ThisWorkbook.Activate

'Update Project Lists
UpdateProjects

'Enable screen updating
Application.ScreenUpdating = True
Application.EnableEvents = True

End Sub

Sub UpdateProjects()

Dim RowSet1 As Integer
Dim ColSet1 As Integer
Dim RowSet2 As Integer

Workbooks("Masterlists.xlsm").Activate
Application.CutCopyMode = True
ActiveWorkbook.Sheets("ProjectList").Activate
'Copy text only columns
ActiveWorkbook.Sheets("ProjectList").Range("C5:F1000").Select
Selection.Copy

'Go back to file running code
ThisWorkbook.Activate

'Unprotect "Project" Worksheet
ActiveWorkbook.Sheets("Project").Activate
ActiveSheet.Unprotect Password:="Pwd123"

'Paste Contents
Sheets("Project").Range("C5:F1000").PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _ 'ERROR OCCURS ON THIS LINE THE FIRST TIME I RUN THE SUB
:=False, Transpose:=False

' ...[Other Code not causing problems here]

'Protect "Project" Worksheet
ActiveSheet.Protect Password:="Pwd123", DrawingObjects:=False, Contents:=True, Scenarios:=True _
, AllowFormattingRows:=False

End Sub