I eventually tried it in IE (I normally use Firefox, currently 3.6.3) and it all worked fine, and then it dawned on me -- My AdBlocker Pro Firefox plugin was preventing me from seeing my own Amazon associate links. D'oh!
A few mouse clicks later and I disabled the rules that were blocking the Amazon product link for the design book I was referencing, and all was fine and dandy! I also directly copied the link URL from the served ad and embedded it in the original post so that even people with the same AdBlock settings as I originally had would have a product link that worked as intended.
Details on ABP settings:
- CTRL-SHIFT-V to open the blockable items pane
- You'll see some items blocked by the Filters "assoc-amazon.com^$third-party" and "ws.amazon.*/widgets/q?$third-party". Click the icon at the far right to disable the rule.
- Reload the page; the Amazon Associates panel/ads should work now.