Like millions of Excel 2000 users, we use a VBA macro to
insert the document pathname into the footer. This has
worked for months and months. Suddenly, this feature
stopped working and reports the VBA message:

Run-time error '50290':

Method 'FullName' of object '_Workbook' failed

The offending line of code highlighted in yellow is:
ws.PageSetup.LeftFooter = "&""arial""&08" &
ActiveWorkbook.FullName

We have found that by changing this line as follows:
ws.PageSetup.LeftFooter = "&""arial""&08" &
ActiveWorkbook.Path & "\" & ActiveWorkbook.Name

everything works fine again. However, we would rather not
go through all our workbooks and change the VBA.

Our IS/IT people always install the latest fixes from MS,
but there's no mention of effects to this VBA property.

Why would this property suddenly stop working?

We are using Excel 2000 Version 9.0.6926 SP-3.

Thanks!