You can check in:
app/design/frontend/package/theme/layout/sales.xml
eg:
http/app/design/frontend/default/modern/layout/sales.xml
Find the block:
sales_email_order_items
Mine is looking like this:
<sales_email_order_items>
<block type="sales/order_email_items" name="items" template="email/order/items.phtml">
<action method="addItemRender"><type>default</type><block>sales/order_email_items_order_default</block><template>email/order/items/order/default.phtml</template></action>
<action method="addItemRender"><type>grouped</type><block>sales/order_email_items_order_grouped</block><template>email/order/items/order/default.phtml</template></action>
<block type="sales/order_totals" name="order_totals" template="sales/order/totals.phtml">
<action method="setLabelProperties"><value>colspan="3" align="right" style="padding:3px 9px"</value></action>
<action method="setValueProperties"><value>align="right" style="padding:3px 9px"</value></action>
<block type="tax/sales_order_tax" name="tax" template="tax/order/tax.phtml">
<action method="setIsPlaneMode"><value>1</value></action>
</block>
</block>
</block>
</sales_email_order_items>
As you see there's the order_total which should pull the info you need.
Edit
If you're not sure of what sales.xml is been loaded then it would be useful to add the sales.xml
from base/default package into you package/theme.
In this way you'll be sure the file used in your theme will have the sales_email_order_items block in it.