One of the first things to understand is that the AHBL is not blocking your e-mail. The people who own the mail server you are trying to send to is blocking you. The AHBL simply publishes a list of IP addresses and hostnames of networks and servers we believe are either abusive, spamming, insecure, or unsafe.
We allow anyone to use our list with the understanding that we are not responsible for any legit mail that may be blocked because of our listings.
If you have specific questions about what might have caused you to get listed, check the Lookup Page and the Listing Policy Page.