It's not you, it's us
We recently started breaking certain social networks out into a plugin based system. This helps us release updates for specific providers out of sync with JFBConnect and has other benefits.
The Pinterest plugin wasn't in the latest release, but I'll email it to you. Can you install this plugin in Joomla and enable it. Then, that tag should go away..
Test and let us know if you run into any issues.. and thanks for pointing this out! It'll obviously be fixed in the next release.
Thanks,
Alex