1.9.1 error in visitor log 'there is no data for this report'

As well as the missing sparklines in the visits overview widget I’m seeing the error above in the visitor log after the second ‘next’. It’s currently set to 20, and works ok if you select a different time period, but has the same problem if you try to set it to show 50 results etc.
It seems to be a problem with this row selector or next screen link.

Got the same issue here: 301 Moved Permanently

I have the same problem. No idea why…

Can you please try this solution there: 301 Moved Permanently

Hi Matt,
That is a fix for the sparklines (which works) but doesn’t fix the error in this thread’s title - there is still ‘no data for this report’ in the visitor log.
Any ideas?