Amazon.com has changed their data API to require that all searches be signed with a secret key, unique to each user. The upcoming version of Tellico supports the new method. However, older versions (i.e. all versions of Tellico for KDE3) do not.
As a result, the Amazon searching no longer works for any version of Tellico released for KDE3. I don't plan to try to backport that support, either.
Sorry, folks. You'll just have to use a different search source.