Domain Mapping not allowing purchase

I have an enom domain reseller account, everything seems to be connected properly.

I have a client who has a domain already mapped and wishes to buy a domain via my site.

However when the search, find the domain is available and then try to click the purchase from the site, they are displayed a blank page!!! No bueno.

Here is an example link of what they are clicking when it says purchase domain that is showing a blank screen (no code when clicking view source):