HTML Validation Issue – WP Email Notification Plugin

Greets:
I’m using the WP Email Notification Plugin, and have a piece of code inserted into the sidebar.php of the Landzilla From The Swamp theme. I’ve narrowed the initial valdiation of the root page output (https://www.urbanlandscapes.org/wordpress/) to two errors.

This is the code from the file that I’ve inserted:

<h2><?php _e(‘Subscribe!’); ?></h2>
<?php email_notification_future_send(); ?>

<form method=”post” action=”maillist/index.php”>
Enter your e-mail address to receive notifications when there are new posts

<input type=”text” name=”email” size=”12″ maxlength=”36″ />
<input type=”submit” name=”submit” value=”sign up” />
</form>

Here is the error output from the W3C HTML Validator…

# Error Line 1165 column 47: document type does not allow element “form” here; assuming missing “li” start-tag.

<form method=”post” action=”maillist/index.php”>

?
# Error Line 1171 column 4: end tag for “li” omitted, but OMITTAG NO was specified.

You may have neglected to close an element, or perhaps you meant to “self-close” an element, that is, ending it with “/>” instead of “>”.

?
# Info Line 1165 column 0: start tag was here.

<form method=”post” action=”maillist/index.php”>

If I remove the ‘ul’ code, it shifts the rest of the sidebar a bit to the right, including the dark green banner for each section the rest of the way down the sidebar.

I’m open to any suggestions on how to fix the code so that it validates without the formatting issue. Thanks much!
Velanche