Creating Nexxon account error

I have follow everything as guided here

http://fgames.4.forumer.com/index.php?showtopic=1447

but i still get this error...may i know what does this means?

thanks a lot in advance

http://img227.imageshack.us/img227/8213/errormh6.png

This is only a guess but maybe something to do with the username?