An answer to this old question, as I just ran into this again. I did a fresh install of 5.5.5 Commercial and revbrowser.dll was missing even though it was listed in externals.txt. I copied it over from 6.6.2 Community and the browser samples work fine in 5.5.5 now.
Bringing the internet highway into your project? Building FTP, HTTP, email, chat or other client solutions?