Ironically enough, this is the only result when searching google for that error. If tell to show even the results it thought too similar (or whatever that functionality is called in English) you will get a bunch more references to this post and to one other result. Also on this forums.
Anyway, let me repeat real quick what it said there: this might be caused by your dll having been compiled with a different version of gcc than you are using to Code::Blocks with.