Pivot Table Filter Not Allowing Item Selection.

Hello,

In an Excel Workbook created with an online Excel Survey, I've suddenly begun getting the following error message, even when I have one or several items selected to filter:

The page at https://excel.officeapps.live.com says:
At least one item has to be in the filter.
Click OK, then select the check boxes for one or more items in the list.

The filter now only works if the 'All' box is selected.
See screen capture here: http://static.commentcamarche.net/cc...P-capture1.png
[The above is true only when working in the Online version,- whether in Chrome, IE, or Firefox-not in full Excel, where all seems to still function correctly.]

Ideas?
Thanks!