Thank you for responding Carms77. I did not think the problem with Zen was only me as I DQ many times on other surveys and I don't get that annoying error on those surveys. I have not seen it recently though. I hope this is because they were aware of the issue and fixed it and not just because I've been 'lucky'. Zen Surveys is one of TT's best surveys right now as far as I am concerned and so I would rather not see this one screwing up.
As for Your Surveys, I dont really have any issues with them myself. My only complaint with this one is the low payout.