I find the whole XML thing difficult so I am sympathetic to your cause here.
It looks to me like there is a discrepancy with your class name and your block XML
ie
class Crusader_CLHomePage_Block_Qwerty extends Mage_Core_Block_Template
and
<block type="core/template" name="homepage" template="crusader/home.phtml">
<block type="crusaderhome/qwerty" name="homeads" as="homeads" template="crusader/homeads.phtml" />
</block>
Let's start with the block type and work backward. I think here I would expect to see something like
<block type="crusader_home/qwerty" ...
and that type would refer Magento to the class
Crusader_Home_Block_Qwerty extends Mage_Core_Block_Template
Continuing to work backward on this tack, the file app\code\local\Crusader\CLHomePage\etc\config.xml would need to be modified to something like
<global>
<blocks>
<crusader_home>
<class>Crusader_Home_Block</class>
</crusader_home>
</blocks>
</global>
It points Magento to all classes starting 'Crusader_Home_Block_*'. And now I think you need to rename your module Crusader_Home instead of Crusader_CLHomePage and change the folder names accordingly...
AND / BUT I strongly recommend you change your module name. Only ever use one capital letter at the start of the module name not three and don't put capital letters in the middle of the name either.
You may want to look into some of the tools available for generating modules. I find them very useful for avoiding typing errors. I use this one by the very clever people at MGT Commerce (it has simplicity on its side) and this one is all-encompassing and an astonishing piece of coding by Silk Software.
***EDIT following comments below
Additionally based on the error log I think the problem is that Magento can't find your class file. So double-check the caches are refreshed or off, particularly XML cache, and that the compiler is off or re-enabled.
I guess it depends on what your trying to add and if it needs to be at a particular point e.g before or after the add to cart button.
If after the addtocart button is ok you can use product.info.addtocart since it calls <?php echo $this->getChildHtml('', true, true) ?>
.
e.g
<catalog_product_view>
<reference name="product.info.addtocart">
<block type="core/text" name="core-text"><action method="setText"><text><![CDATA[<div>Test</div>]]></text></action></block>
</reference>
</catalog_product_view>
Update:
If you wrap the text in a div as I have updated above it will work in the default theme like below. But this may not work quite right in other themes like the new rwd.
Best Answer
The only places you can put your extension block in the checkout only via the checkout is above everything, below everything and above the coupon code block.
To put it above the coupon you need to change the extension layout to this:
The name of the custom block must be
checkout.cart.extra
.In order to position it below the coupon section change the layout to this:
then edit
app/design/frontend/{package}/{theme}/template/checkout/cart.phtml
and add this line:right below