Help with a search and add product

[ChurchMedia]

I'm trying to create a product that will search a template and add some code to it. I've based it off of a couple of similar hacks. Mine will add a payment image under the payment bits for subscriptions. The code looks right, but when I try to install it, it just hangs. I know I could release it with a manual template edit, but I'm trying to make it really simple.

Any help is appreciated.

Here is the code:

PHP Code:

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

<product productid="PaymentImages" active="1">
    <title>Payment Images</title>
    <description>Adds Images to Subscription Payments</description>
    <version>1.0.0</version>
    <url></url>
    <versioncheckurl></versioncheckurl>
    <dependencies>
    </dependencies>
    <codes>
        <code version="1.0.0">
            <installcode>
            </installcode>
    <uninstallcode></uninstallcode>
    </code>
    </codes>
    <templates>
    <template name="subscription_payimage" templatetype="template" date="1161260494" username="ChurchMedia" version="1.0.0"><![CDATA[
    <img alt="$method[classname]" src="/images/payments/$method[classname].gif" border="0"><br /><br />    
    ]]>
</template>
    </templates>
    <plugins>
    <plugin active="1" executionorder="5" product="PaymentImages">
            <title><![CDATA[Payment Images]]></title> 
            <hookname>cache_templates</hookname>
            <phpcode><![CDATA[$globaltemplates[] = 'subscription_payimage';]]></phpcode>
        </plugin>
<plugin active="1" executionorder="5" product="PaymentImages">
        <title><![CDATA[Add Images to Subscription Payments]]></title>
        <hookname>paidsub_order_paymentbit</hookname>
        <phpcode><![CDATA[
                $search = '$form[hiddenfields]';
                $vbulletin->templatecache['subscription_paymentbit'] = str_replace($search,$search.$vbulletin->templatecache['subscription_payimage'],$vbulletin->templatecache['subscription_paymentbit']);
        ]]></phpcode>
    </plugin>
    
    </plugins>
    <phrases>
    </phrasetype>
    </phrases>
    <options>
    </options>
    <helptopics>
    </helptopics>
    <cronentries>
    </cronentries>
    <faqentries>
    </faqentries>
</product>