Well, the fact that you cant do a lookup is normal. See:
http://www.spamhaus.org/faq/answers.las ... hnical#122
Once you have added spamhaus and removed the other, try restarting mailwasher services (if you havent already), thats all I did and it started working.
Another thing I used to test it, which will be useful, as it also ticks the counter for RBL's is send an email to
nelson-sbl-test@crynwr.com from an email address on your domain. It will trigger a bot to test your mailserver.
Below is part of the email you receive as an auto-reply.
"Testing your SBL block. See
http://www.crynwr.com/spam/ for more info.
Please note that this test will not tell you if your server is open for
relaying. Instead, it tests to see if your server blocks email from IP
addresses listed in various blocking lists; in this case, the SBL list."
Hope this info helps a bit.