The PivotTable field name is not valid (error)
 

Hey, wonder what I might do here. Using excel 2007 to link to a sharepoint
"list". I then "pivot" this list for a variety of reports. However, when I
then, say, the next day, choose Data, Fresh, and then go back to the pivot
table and right click on it to refresh, and see change, I get an error:

"The PivotTable field name is not valid. To create a PivotTable report, you
must use data that is organized as a list with labeled columns. If you are
changing the name of the PivotTable field, you must type a new name for the
field."

And of course, I am not seeing the refreshed information in the pivot table.
Any idea what is going on here? What can I do to keep the Pivot Table
"locked" on the data set, even if I refresh it?

Thanks!

PatK