Menu adds line break – but only on IE and Firefox

P.S. The line break seems to be limited to the size of the header image. (The line break is right at the edge of the image. But this only happens in IE and Firefox.)

https://validator.w3.org/check?uri=http%3A%2F%2Fwww.michaelgaither.com%2Fhome%2F&charset=%28detect+automatically%29&doctype=Inline&ss=1&group=0&verbose=1&user-agent=W3C_Validator%2F1.3

Scroll down to the errors around 265.

Odd. It seems fine here on the actual page. Unless I’m missing something obvious:

<div class="menu-main-menu-container"><ul id="menu-main-menu" class="menu"><li id="menu-item-43" class="menu-item menu-item-type-custom menu-item-object-custom current-menu-item current_page_item menu-item-home menu-item-43"><a href="https://www.michaelgaither.com/home/">HOME</a>
<li id="menu-item-45" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-45"><a href="https://michaelgaither.com/home/music">MUSIC  AND STORE</a>
<li id="menu-item-2630" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-2630"><a href="https://www.michaelgaither.com/home/shows">CALENDAR</a>
<li id="menu-item-46" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-46"><a href="https://michaelgaither.com/home/video">VIDEO</a>
<li id="menu-item-49" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-49"><a href="https://michaelgaither.com/home/gallery">GALLERY</a>
<li id="menu-item-417" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-417"><a href="https://www.michaelgaither.com/home/podcast">PODCASTS</a>
<li id="menu-item-44" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-44"><a href="https://michaelgaither.com/home/press">PRESS KIT</a>
<li id="menu-item-2629" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-2629"><a href="https://www.michaelgaither.com/home/contact1">CONTACT</a>
</div>

[Moderator Note: Please post code or markup snippets between backticks or use the code button.]

Could I possibly be missing a closing </dev> tag in this section?

[41 lines of code moderated as per the Forum Rules. The maximum number of lines of code that you can post in these forums is ten lines. Please use the pastebin]

I removed this <div class="menu-main-menu-container"> from line 265 and the </div> from this code </ul></div> </ul> at line 275 and it looked ok in IE9.