Are you having problems with the bot blocker? Here are a few common problems, but it's somewhat possible that there is a bad interaction between a broser and a server somewhere; if none of these suggestions work, email the maintainer.
Too many questions!
Each post you make should only require answering one question. If you answer the question and it doesn't work, something's gone wrong somewhere.
Keep the following in mind, though: if you hit the Return (or Enter) key at the end of your answer, in most browsers this will automatically submit the form. With these comment forms, there are two submit buttons---one to preview and one to actually post---and Return will effectively click the Preview button. If you haven't typed anything in to the actual comment field yet, the preview itself will be empty... and you'll have a new botblocker question. So, remember to either type in your comment first or, if you do the question first, to hit Tab or click the comment field to start entering there.
This question is too hard!
I've tried to make the questions all easy (for humans), but some are certainly easier than others. If the question is too hard, click the Preview button and you'll get a different one.
It says something about an overload!
Because I need to keep a file around between when you're presented with a question and when you answer it (to see what question you're answering, in order to check your answer), there's a limit to how many "sessions" can be open at once. That number, and the length of time a session can be kept open, are both configurable, but under one of the heavy spam sieges that happen from time to time, BotBlock will run out of available files. At those times, the question field is replaced with the text "Sorry! Spammers have temporarily overloaded the system. Reload this window in a little while to try again." You can hit the Preview button at any time to try for a fresh question.