Problem after Log/Data delete

Hello,

The plugin was working very fine until I checked “Delete Log/Data”. After this without touching anything on the code I receive a popup “Please rate only 1 post at a time” when I try to rate some page.

I did try to uninstall/delete mysql tables etc. etc.

Does anyone had the same problem?
Thanks.

http://wordpress.org/extend/plugins/wp-postratings/