If I'm wrong, someone please correct me. This is (I think) the correct syntax:
Code:
{if $usertype eq "C"}
{if $login eq "" }
{ include file="auth.tpl" }
{else}
{ include file="authbox.tpl" }
{/if}
{/if}
Code:
{if $usertype eq "C"}
{ include file="auth.tpl" }
{elseif $login eq "" }
{ include file="authbox.tpl" }
{/if}