[Dragonsys]

Didn't make a difference. Here is the full xml file, just in case

<?xml version="1.0" encoding="ISO-8859-1"?>

<product productid="dso_fa" active="1">
	<title>DSO - Font Awesome</title>
	<description>Adds Font Awesome v4.4.0 support to vBulletin</description>
	<version>1.0.0</version>
	<url />
	<versioncheckurl />
	<dependencies>
		<dependency dependencytype="vbulletin" minversion="4.1.8" maxversion="" />
	</dependencies>
	<codes>
		<code version="1.0.0">
			<installcode><![CDATA[$db->query_write("
				INSERT INTO ".TABLE_PREFIX."bbcode 
					(bbcodetag, bbcodereplacement, bbcodeexample, bbcodeexplanation, twoparams, title, buttonimage, options) 
				VALUES 
					('fa', '<i class="fa %1$s"></i>', '[fa]fa-male[/fa]', 'Use Font Awesome icons. For a list of available icons see here: https://fortawesome.github.io/Font-Awesome/icons/', 0, 'Font Awesome', '', 31)
			");
			build_bbcode_cache();]]>
			</installcode>
			<uninstallcode><![CDATA[$db->query_write("
				DELETE FROM ".TABLE_PREFIX."bbcode WHERE bbcodetag = 'fa' LIMIT 1;
			");
			build_bbcode_cache();]]>
			</uninstallcode>
		</code>
	</codes>
	<templates>
	</templates>
	<stylevardfns>
	</stylevardfns>
	<stylevars>
	</stylevars>
	<plugins>
	<plugin active="1" executionorder="5">
			<title>Font Awesome CSS</title>
			<hookname>parse_templates</hookname>
			<phpcode><![CDATA[$dso_fa_css = "	<link rel=\"stylesheet\" type=\"text/css\" href=\"./DSO/font-awesome-4.4.0/css/font-awesome.css\" />";

$template_hook['headinclude_css'] .= $dso_fa_css;]]></phpcode>
		</plugin>
	</plugins>
	<phrases>
	</phrases>
	<options>
	</options>
	<helptopics>
	</helptopics>
	<cronentries>
	</cronentries>
	<faqentries>
	</faqentries>
	<navigation>
	</navigation>
</product>

It is strange, as I have not had a problem with this in any other plugin I have written, so I'm sure it has to be something I am just missing from staring at the screen...