Validation Helper

Error

ArgumentError at /faca-sua-insricao
invalid byte sequence in US-ASCII
file: utils.rb location: gsub line: 153


sinatra.error	
#<NoMethodError: undefined method `errors' for nil:NilClass>

Helper.erb

def field_validation(target, field)
   "<span class=\"field-validation-error\">#{target.errors[field][0]}</span>" unless target.errors[field].empty?
end

View.erb

<td><%= field_validation(@u, :first_name) %><input type="text" name="first_name" value="<%= session[:user].first_name %>" id="first_name" class="validate[required]"><br /><label for="first_name"><%= t[:forms][:firstName] %></label></td>