[Plugin: Video Thumbnails] Libcurl Error for Vimeo

Running 1.8.1

I am getting errors similar to the following for Vimeo embeds:

Error retrieving video information from the URL http://vimeo.com/api/v2/video/<video id>.php.
Libcurl error 22: The requested URL returned error: 404. If opening that URL in your web browser returns anything else than an error page, the problem may be related to your web server and might be something your host administrator can solve.

Clicking on the URL leads me to a “not found” error.

Tested that I could retrieve the thumbs in Vimeo’s API playground (no token, PHP). I did notice this URL on the page:

http://vimeo.com/api/rest/v2?format=php&method=vimeo.videos.getThumbnailUrls&video_id=<video id>

Did Vimeo change the way thumbs are retrieved, or does this have to do with the videos being private/unlisted? Thanks in advance!

http://wordpress.org/extend/plugins/video-thumbnails/