Error with checkboxes

The module was showing an extra checkbox (without any title) when I don't select all the roles to be displayed in the registration form.

We have been working on that:

 foreach($display_roles as $role){
    $role_name=db_result(db_query("SELECT name FROM {role} WHERE rid=%d",$role));
    
    if(in_array($role,$approval_roles)  and ($role_name!='')){
    $role_name.=" <i>*needs administration approval</i>";
    }
    $roles[$role]=$role_name;
    }
    
    foreach($roles as $role){
        if($role == ''){
            unset($roles[$role]);
        }
    }

;)
I attach the .module file