Error: Cannot open pivottable source file

A little different than the write-up in the Excel Knowledgebase. I have a
spreadsheet heavily laden with pivot tables stored in a Sharewaves site.
Most of the pivot tables tables work when I open the spreadsheet.

However, some pivottables are getting their data based on a "Name Range"
that I created:
=OFFSET('Sheet1'!$A$1;0;0;COUNTA('Sheet1'!$A:$A);COUNTA('Sheet1'!$1:$1))
When I try updating this Pivot table, I get "Cannot open PivotTable source
file 'worksheet name.xls'.Any idea what is wrong?