Multiman black screen PS3 FAT

Hi guys.

I have just installed HFW 4.91.1 on PS3 FAT and HEN 3.3.0 throught ps3xploit.me , then i installed multiman, webman and irisman.

I have a problem with Multiman; most of the time, it doesn't start, and a black screen appears. If I force a reinstall, it starts the first time, but then not anymore... If I restart the console several times, it might start again. Why does this happen? Is Multiman indispensable?

thankss