My apologies for not responding right away, but your emails were going to my junk folder.
I repaired the issue by changing line 35 of class.DownloadStats.php.
From this: $udl[“{$index}”] = isset($udl[“{$index}”])?$udl[“{$index}”]+1:1;
To this: $udl[“”.$index] = isset( $udl[“”.$index] ) && is_numeric( $udl[“”.$index] ) ? $udl[“”.$index]+1 : 1;
Hopefully this will be fixed in the next update.