It looks like it is just a syntax error:
replace this line:
<form action="" method="get" name="CouponCode"><input name="txtPromoCode" type="text" /></<input name="Button" type="Submit" />form>
with:
<form action="" method="get" name="CouponCode"><input name="txtPromoCode" type="text" /><input name="Button" type="Submit" /></form>