I just tried those links and most of the others on that library page, and they all worked for me. I suspect you encountered some temporary condition; for example, maybe a library build or update hadn't finished, or maybe there was a problem with some server.
<s>All the links are working fine except the one I was talking about, "Cloud Administration Guide". The html link is pointing to http://docs.oracle.com/cd/E24628_01/doc.121/e28814/toc.htm which does not work from the Netherlands.</s><br>
And now it works.
However, when searching for "create database" in Cloud computing homepage (http://docs.oracle.com/cd/E24628_01/index.htm), then click on the first returned result (Figure 11-3 Create Database Zone: Targets - from the book Enterprise Manager Cloud Administration Guide), it's still failed with page 404.
It's still broken with following msg : We're sorry, the page you requested was not found. We have recorded this error (404) to help us fix the problem.
How to help you more to make us able to read the doc ?
I passed this along to the head of the team that creates and maintains the documentation libraries. The problem was that the library search index had not been synchronized with the library content. That has been fixed.