auto updating circular links

Hi,

I have a master workbook with links to data on a number of data entry
workbooks, all contained in a network folder. Each of the data entry
workbooks then has some charts which are linked back to aggregated linked
data on the master workbook. A bit circular, I know.

The intention is a user enters data on the data entry workbook and runs a
macro which updates the charts. The macro opens and closes the master
workbook as a means of updating the links.

Problem is that the updating only works intermittently, yesterday it would
only work on my PC and not on others (all Excel 2000), today it won't work on
any. I thought I had fixed yesterdays' problem.

The macro code I am using is:
Sub Update_Graphs()
Workbooks.Open Filename:= _
"G:\Performance Measures\Master.xls", UpdateLinks:=3
Workbooks("Data Entry 1.xls").Activate
Workbooks("Master.xls").Activate
ActiveWorkbook.Save
ActiveWindow.Close
End Sub

I've tried various sequences of the .Activate function and values for
UpdateLinks with no success. Yesterday's problem appeared to be fixed by
changing the file address from UNC format to G:\.

The update fails at the first link, ie the link in the master file is not
updated.

The only way I can reliably update the chart is to manually have both files
open at the same time, or open each file separately (master first) allowing
the links to update.

Any clues ?

Thanks in advance.