I'd appreciate it if you wanted to boycott PPrune, to do it ASAP - makes it much faster for the rest of us
As for these "captchas" you'll find they're VERY common these days with almost every forum you try to register for. I am the first to admit I hate them (can never read them properly, despite being 20/20) but they're a good deterrent-for now-against automated bots registering and spamming.