Voting fails replacing widget with frontpage

When clicking on a vote widget the widget gets replaced with the frontpage. This may be caused by the multilanguage systems in my installation, and some custom url handling, but regardless of that it can be fixed by simply adding a / at the beggining of the url at rate.js (line 28)

var q = '/?q=rate%2Fvote%2Fjs&widget_id=' + data.widget_id + '&content_type=' + data.content_type + '&content_id=' + data.content_id + '&widget_mode=' + data.widget_mode + '&token=' + token + '&destination=' + escape(document.location) + '&r=' + random;