Pivot table not including new data

Hi,

I'm having a problem at the moment with a pivot table not including new data
being added to a spreadsheet (Excel 2007).

The data added represents survey results for each week. The pivot table
then summarises these into columns with a heading of "July 08 Week 4", as an
example.

New data is added to a "Raw Data" spreadsheet and the pivot table is in a
separate spreadsheet. This has been working fine for a long time, until it's
my turn to update the data.

So, I have added new data to the "Raw Data" spreadsheet and it is labelled
"July 08 Week 5". The spreadsheet has been saved and I then refresh the
pivot table on spreadsheet #2. The pivot table seems to refresh, but it
doesn't add in the Week 5 data.

I've checked the data source to make sure it is including the cells that
contain the new data and that appears to be fine.

Is there any reason why the new data would not be included in the pivot table?

Hopefully this is enough information, but please let me know if anything
else would help.

Thanks,
Scott