Minor fixes for 1.4 patch 1

[RussJohnson]

Hi all,

I just installed PostAffiliate Pro version 1.4 patch 1 and found a couple minor glitches that I'd pass on.

In the top-level header.htm file:
-<link rel="stylesheet" type="text/css" href="./affiliates/templates/default/style1.css">
+<link rel="stylesheet" type="text/css" href="./affiliates/templates/new/style1.css">

and in the langs/spanish.php file:
-define('AFF_G_UNAMEEXISTS', 'Este nombre de usuario ya existe, elige otro';
+define('AFF_G_UNAMEEXISTS', 'Este nombre de usuario ya existe, elige otro');