The problem appears to be in having an older version of "framework/library.php".
You can probably make sure you have the latest version of eCart installed and then update and re-upload that file... you may just need to upload that file if you ran the checkout wizard with the latest version of eCart.
Another solution is to bypass the problem and update liens 75-82 from:
<?php
// WA eCart Redirect
if ($VetProCart->redirStr != "") {
if (function_exists("rel2abs")) $VetProCart->redirStr = rel2abs($VetProCart->redirStr,dirname(__FILE__));
header("Location: ".$VetProCart->redirStr);
die();
}
?>
to:
<?php
// WA eCart Redirect
if ($VetProCart->redirStr != "") {
header("Location: ".$VetProCart->redirStr);
die();
}
?>