I believe that you're using a very old version of the embed bbcodes; you can see all of the URLs the current UBB.threads regex supports
here (your URL looks like group 5).
In the install folder for UBB.threads there should be a text file for the new BBCodes as well as entries for the included styles with that build:
BBCodes: install/custom_codes/tags.php
Styles: install/styles/
Which can be imported from:
BBCodes: CP -> Tools & Information -> Content Rebuilder -> Custom Tag Editor tab -> Import New Tags
Styles: CP -> Display -> Styles -> Import Style
You will need to remove or disable older versions of styles or bbcodes before running newer versions of the tags.
