Please make something good from it.
either hide the button for "own content" (thats sure false, because the entire thread is not the original posters content)
or give the original poster points for each rating of her/his proposal
see also "How to avoid ratings users give just for gaining points":http://developer.qt.nokia.com/forums/viewthread/900/
[EDIT] "=b" is the thumbs up icon ;) and "Cannot rate..." is the text of the hint on mouseover