I tried with my gmail account and I was told that was banned as well. Thanks for the info though.
Which would further indicate that the problem lies with your IP address rather than your e-mail. The board will log the IP address of your computer/router (as given by your ISP) when you visit so when you attempt to register, it doesn't matter what e-mail account you use, a rogue IP may already have killed your chance of registering.
You don't say how much of a complete moron you are when it comes to IP addresses, so here is a potted guide ... every computer on a network (which is basically all the internet is) has a unique numerical address identifying it. The address will look like this: xxx.xxx.xxx.xxx
So, what does this mean in practice ...
When you type www.b5tv.com into a web browser, the first thing your browser does is check with another computer (known as a Domain Name Service server - normally one of your ISP's) to find out the correct numerical address for the computer hosting the website. It already knows your computers IP address so once it finds the target address it can put you in touch with it.
Spambots, like other computers, will provide an IP address when making contact with a website, and the owners of the sites can take action to block that address, or a series of addresses, to try and stop it happening again. Kind of like hitting the "Ignore" button when your cellphone rings and caller ID indicates this is someone you don't want to talk to.
Some ways to try and isolate and, hopefully, resolve this problem are:
1. To make contact with the admin of the board and see if you can find out exactly why you are having problems and whether there is anything they can do to solve them.
2. Try registering with the site from another computer (preferably one using a different ISP). If you can do that, you have your answer, although you may still not be able to post from your own computer even once you have registered.
3. See if your ISP can allocate you a different IP address, or even better a dynamic one. A dynamic IP basically changes every time you go online so you can avoid this type of thing ... unless, of course, the site has barred an IP range that covers that whole ISP, which they might have done if they have been receiving spambot visits from computers using those addresses.
4. Should 3 prove to be impossible, or not solve anything, change your ISP if it still appears that the IP address is the issue.
Really, you shouldn't be trying options 2, 3 or 4 without getting some ideas from the site itself. And you should only venture as far as option 4 if you really really want to register with the site, and don't care what it takes.
Hope this helps (and didn't veer too far into Geekland!),