SharePoint: Request Failed

Hi

Can anyone help with this issue that's suddenly emerged?

I have a number of CSVs in Sharepoint.  The data refreshes in the service fine, however when I attempt to refresh in the desktop I get a 'SharePoint: Request Failed' message relating to one of the csvs.  Every attempt I make to refresh brings the same error but each time it specifies a different csv.  

This refresh has worked absolutely fine for at least 9 months and nothing in the desktop, the service, or the csvs themselves has changed.

Thanks for any help.