If you get protection  errors it may be that your code is trying to alter
protected parts of the workbook. The way to deal with this is, in your code
to turn protection off, make the changes, then turn protection back on.

So I changed the code to this....

ChDir "\\tangent1\PLP"
Workbooks.Open Filename:="\\tangent1\PLP\Ongoing Summary.xls",
UpdateLinks:=3
ActiveWorkbook.Save
ActiveWorkbook.Close
ActiveWorkbook.Unprotect
ActiveWorkbook.UpdateLink
ActiveWorkbook.Protect

Sitll doesn't work... I get the same error  message Run time error
1004 you cannot run thios comman on a protected sheet.

Any other ideas???

Have you tried doing this manually while recording a macro?

Instead of:

ActiveWorkbook.UpdateLink

Try:

ActiveWorkbook.UpdateLink Name:=ActiveWorkbook.LinkSources

Yes I did in a test workbook environement... adn came up with this

ChDir "\\tangent1\PLP"
Workbooks.Open Filename:="\\tangent1\PLP\Ongoing Summary.xls",
UpdateLinks:=3
ActiveWorkbook.Save
ActiveWorkbook.Close
ActiveWorkbook.Unprotect
ActiveWorkbook.UpdateLink Name:= _
"\\tangent1\PLP\Ongoing Summary.xls", Type:= _
xlExcelLinks
ActiveWorkbook.Protect

Which worked in my test workbook environment but fails in my real
environement with

I m pretty sure it s the UpdateLink command. Do you know how to do a
step-by-step debug of the macro?