Updates on this. I'm still not getting any error messages event thought it isn't crossposting.

However, I went to edit my new entry today (which hadn't been crossposted) and noticed that the "ticky-boxes" for crossposting weren't clicked, even thought they had been active in my original post. I clicked them, made my change, hit "update changes" and voila, it crossposted the right entry all of a sudden.

Hope this helps.