Few changes

1) removed the notice if the contrib isn't for an event (we are using it for donation and membership)
2) added a comment about not forgetting to add the contrib page as a valid referer on ogone (mofo, this one took a while to identify)
3) I add an error on ogone if one of the field contained a éö... char. Still haven't found the source of the encoding problem, but implemented a workaround (strip the accent). don't you have this PB?
4) and obviously defaulted to french as the language ;)

As a sidenote: are you coming to civicon? and we are organising an administer/poweruser training next week in brussels if you know someone....