Hi, I think you need to find a better/newer copy of the dutch dictionary. I know there was an option for leniency here before, but I removed it: because it made it impossible to improve the hunspell support in lucene when it just silently did the wrong thing.
There are some dictionaries out there with bugs like this, especially old ones, hell I even found one with an executable file embedded inside of it!
My advice is to find the most recent version of the dictionary, usually that works best.