The Pro Limewire will not prevent porn files. Did you look up the files with Bitzi to see if they were rated? If you checked Bitzi and the file(s) were unrated then it's up for grabs what you might be about to download.
When I start to download a file with no Bitzi rating I let it get to about 10% and then preview it with a program I have to see if it looks like a good file. Do a Google search for VideoLan and download the free software...it's a video player that plays most files.