For the record, I did respond to your initial request. I am sorry that it took me 6 hours to respond to your second request, but supporting a free plugin is not my sole source of income. ;-)
I ran some tests on my staging system and it seems to be blocking Vimeo's iframe just fine. Anything that is held in the $content variable will be blocked (with the exception of anything before the 'more' tag on a post). Looking at the site link you sent earlier, you have this on a "page" (as opposed to "post"). This should be no problem for the plugin as long as you are appropriately blocking pages. Have you checked the following:
- Do you have the plugin set to block pages by default? (The default setting is no, but it will have a bearing on the next check.)
- If pages are not blocked by default, did you set a custom field on the page to block it? (See the plugin FAQs on how to do this.)
Hope that helps.