On the download page [1], there is a link to "apt://pitivi/" but the
link should be "apt://pitivi".

Synaptic throws an error otherwise, looking for 'pitivi/'
This is strange... because if you look at the source code, there is no trailing slash at the end. It looks like this:
           or simply click <a href="apt://pitivi">this link</a>

I have noticed this behavior on Chromium, but not on Epiphany or Firefox. I just filed a bug here: http://code.google.com/p/chromium/issues/detail?id=30283