I'm trying to register on the Runic Games forums (to discuss Torchlight 2), but whenever I try to register my account it keeps saying:

Your IP ----- has been blocked because it is blacklisted. For details please see http://search.atlbl.com/search.php?q=174.61.155.24.
An entry on the blaklist may have several reasons:
1. You are a well-known spammer.
2. Last time a well-known spammer was using the dynamic IP address which you got from your ISP (Internet Service Provider).
3. Your ISP is well-known for a lot of spamming customers and is not fighting against spammers.

Anyone know why? I am not a well-known spammer and I don't think my ISP is well-known for a lot of spamming customers. This has never happened before. I went to this site http://whatismyipaddress.com/blacklist-check and apparently I'm blacklisted on l2.apews.org, dyn.shlink.org, zen.spamhaus.org, and pbl.spamhaus.org. Every other site is green. Could that be why?