register.php doesn't execute exactly

[Sh4z0n]

hi all,

i've copied my forum/register.php in my root dir ( / ) because i need to do register my user on a page displyed on my homesite.

....but there is a problem... when a submit registration an error occured: "username or email or password hasn't been inserted"
.... i couldn't understand why and so a put an: "echo $username;"
before if sequences but it display nothing, appear empty...

thanks in advance