No products displayed in dropdown box when adding products to specials

What version of Zen Cart are you using?
1.3.8a

What addons have you installed? When?
- Cherry Zen

• MSRP

In what ways is your site customized or different from a brand new uncustomized install?
Very much customised

HAVE YOU LOOKED IN THE FAQ AREA for answers to your question? (ie: a search for your error message or what you want to edit/change, etc)
Yes

Does anyone know which files are affected pertaining to the above issue? I want the on-sale products to be listed on the specials page but there are no products listed on the dropdown box. The same thing is true for the featured products page.

Products already on Special will not show ...

Product with a Product Type that is set to not show the Add to Cart will not show ...

Check the Product Type setting in the Catalog ... Product Types ... EDIT ... and ensure that the:

This Product can be added to cart:

is checked ...