[CC]

It would appear that some are not giving consideration to the two different registration forms.

Remeber, there is a Checkout sign up page AND and general register page.

They dont have the same sign up fields.
The general sign up page does not ask for the a Name twice, the checkout sign up does.

So on the general signup you have no name field to carry across twice, hence the error.

Either create two templates for this or use this .js code:

function InitSaveVariables_shipping(form){ 
s_address = form.s_address.value; 
s_address_2 = form.s_address_2.value; 
s_city = form.s_city.value; 
s_state = form.s_state.value; 
_s_state = form._s_state.value; 
s_country = form.s_country.value; 
s_zipcode = form.s_zipcode.value; 
} 

function copybilling(form){ 
if (form.copyb.checked){ 
InitSaveVariables_shipping(form); 
form.s_address.value = form.b_address.value; 
form.s_address_2.value = form.b_address_2.value; 
form.s_city.value = form.b_city.value; 
form.s_state.value = form.b_state.value; 
form._s_state.value = form._b_state.value; 
form.s_country.value = form.b_country.value; 
form.s_zipcode.value = form.b_zipcode.value; 
} 

else { 
   form.s_address.value = ""; 
   form.s_address_2.value = ""; 
   form.s_city.value = ""; 
   form.s_state.value = form.b_state.value; 
   form._s_state.value = ""; 
   form.s_country.value = form.b_country.value; 
   form.s_zipcode.value = ""; 
   } 
}