Get ? instead of   when using in Wiki

I have incorporated Fckeditor into my TikiWiki application for creating WIKI pages, and it works fantastic, except that anytime it encounters a   it returns a ? instead of a blank space. I thought it might be the Wiki app, but HTMLAREA works fine and does not do this. I would use HTMLAREA, but I REALLY LIKE Fckeditor!
If anyone knows how I can filter this or correct it please let me know

Many Thanks
Biffer