Hi Laura,
Since you wrote to me privately, I had a sudden realisation!
That Error 404 is produced because you have not loaded a page "blog.html" to your server. In other words, it is not a Nabble problem!
You need to create a page "blog.html" and upload it (It's where the link on the menu bar points, so you must have a file with that name on your server). That page needs to contain all your standard stuff (background colour, site name, menu bar, etc) plus the embedding code your posted:
<a id="nabblelink"
href="http://authentic-choice-consulting-blog.50175.x6.nabble.com/Thoughts-from-a-Tulip-Bed-tp3.html">Thoughts
from a Tulip Bed</a>
<script src="http://authentic-choice-consulting-
blog.50175.x6.nabble.com/embed/p3"></script>
(BTW: You can get code to appear properly in Nabble by adding it in < raw> tags. There's an option to produce them under the "MORE v" button.)
The blog should then appear properly embedded on the page.
Volunteer Helper - but recommending that users move off the platform!
Once the admin for GregHelp now deleted.