It appears that some users are having problems when registering to this site.

The common complaint is that one cannot use the same E-mail address with different user names.

That is a safety feature and is normal!

There is only one way to solve this and that is to get a new e-mail address.

You can do this one of two ways:

ONE: 

Call your Internet Service Provider and request a second e-mail address. Most ISPs will allow you to have multiple email addresses free of charge.  Write down your new address and follow these instructions if you are using Outlook Express.

http://www.homeandlearn.co.uk/BC/bcs3p6.html

http://www.homeandlearn.co.uk/BC/bcs2p1.html

Things should work fairly similar with Thunderbird. Sorry I don't have instructions at this point.

TWO:

Set up an online e-mail account ( free )

For this example we are using Gmail, a service from Google. I highly recommend it.

Here are the tutorials on how to set up a Gmail account. This is by far the easiest way to get a new and free email address.