Featured Image box not showing

Hi,

I got a wordpress developer to build me a custom coupon plugin (http://www.skintnation.com/deals).

As a result, I could only add posts to the coupon posts and not single-page posts. The only way to add posts to single-page posts was to disable the plugin; the featured image box would then show on single-page posts.

Fortunately, I got some developers who changed the code so that now I can add the featured image to single-page posts but, as a result I now can’t add a featured image on coupon posts. They say that the code can’t be changed so the featured image shows on both post-types.

Why don’t you just ask the original developer to change the code, I hear you ask? Well, after the job was completed he stopped responding to my messages.

Is it possible for someone to look at the code and tell me what code I need to add/change in order for me to add featured images on both single-page posts and coupon posts. Indeed, is it even possible to have the featured image box on both page types?

I wasn’t sure where to post this so if it’s in the wrong forum; my apologies.

Thanks