Open multiple spreadsheets and pull data

I'm writing an update routine that keeps 2 EXCEL 2010 spreadsheets in-sync.
I'm using this code to open the first spreadsheet and read data into variable:

Workbooks.Open ("\\server\share\Spreadsheet1.xlsx")
set rgePROGRESS = Worksheets("xxxx").Range("A2:C341")

(code works fine)

Then I read local (or try to read) spreadsheet:

Dim AddressSheet As Worksheet
Set AddressSheet = Worksheets("Dups")
FinalRow = AddressSheet.Cells(65536, 2).End(xlUp).Row
Set rgeDUPS = Worksheets("Dups").Range("A2:I" & FinalRow)

(code works fine)

The following code fails by trying to write into a worksheet called "Dups"
on the network spreadsheet:

For i = 1 To rgeDUPS.Rows.Count
wellno = rgeDUPS.Cells(i, 3).Value

For k = 1 To rgePROGRESS.Rows.Count
If rgePROGRESS.Cells(k, 1).Value = wellno Then
Worksheets("Dups").Cells(i, 8).Value = rgePROGRESS.Cells(k,
3).Value
End If
Next k

Next i



Thanks for any help . . .