I guess the title says it all... Sorry it took so long. You can get Nvu 0.50 from its official site or from my personal mirror. If you want to build Nvu 0.50, this is the document you are looking for.

Reminder: when you start Nvu 0.50 for the first time, you're asked to issue a "ping" to our stats server. Please accept it. We store nothing but the time of your ping, the stats are available to anyone, and it helps us counting how people have really downloaded and launched the application. Thanks a lot.

Tristan Nitot, MacNN, linuxfr.org Robert Accettura