OK.. sorry this is a bit behind the times... had a major crash and had to rebuild my OS....

Yes, No_Account is a bug in the programming that should only appear if you have two conditions existing... the cart is at 0 dollars and you have the checkout using email only checked! this was occurring when you have free products and no account needed for getting them.... I've also had this ghost on me when I was trying to create a one page checkout... I wasn't passing the cart info along right...

On a normal install, this shouldn't popup unless you are giving things away or email only checkout....

Code:
/* COWOA - Set all fields to No_Account for free products */
if ($_SESSION['cart']->show_total() == 0 and COWOA_EMAIL_ONLY == 'true') {
So basically, this bit is setting everything to a default value, getting info 'No_Account' from your language file... reason I haven't even tried fixing this yet, I haven't needed it to work right, Theirs better mods to use for free downloads...

I didn't see any info on what you did to get the code to fire... commenting out the code would work too, but still not solving the cause of the problem, unchecking the allow email only checkout may work too...