Moderation Plugin spam

We are running WPMU (not current version, not even 3.0 but we are hoping to upgrade soon). We use the moderation plugin but I am constantly seeing spam marking blogs, posts and comments as spam.

It usually stars with: Language or Spam and then a number like - tJ3AOT oqdoendnovei, and then a URL.

Has anyone else had this and what an I do about it. We have to go through so much of this before we get the the real blogs that need to be moderated.

Thanks,
Helen