[PC Doctor]

Hmm, check the syntax, make sure you typed everything correctly.. make sure you have all { and }'s.

Where it says {if product.variantid || ... the next line says {include file="customer.... this line makes it display the select options button, and then under that the {else} and then {include file="cust... is how it displays the regular add to cart buttons. Basically, if there are product variants or options, show select options button, or else (no variants or options) show the add to cart button. So yeah, check that you typed everything correctly.

If it still doesn't work right, check the following options:

Admin > General Options > Appearance Options > Under Displaying Products, Check 'Enable Buy Now and Add to Wish List buttons in the product list'
Admin > General Options > Module Options - Product Options > Check 'Redirect a customer who clicks the 'buy now' or 'add to wishlist' buttons of a product with options to the product details page'

That's all I can think of for now, let me know if that helps..