3.0.3 ?? And me too the way I got it to work /enable hen is by setting the homepage of my ps3 browser to the ps3xploit server it is also a hen enabler once hen enables this way the toolbox seems fine... wait now it has disappeared... Weird Does work though I even used it to install some waves and a theme and new font worked then i think after a reboot and enabling hen again it is gone now.
You might try reinstalling it if it happens to disappear on you as well But IDK I would let the dev's Figure it out And patch ...Something before I gave it a go again myself... Learned that the hard way Quite recently...
my situation was a little diffrent I had to reinstall well everything And upon getting all the HFW And HEN stuff done finally...

I reinstalled all of my Homebrew MMcm WMmod irismanager etc... Saving hentoolbox for last because it seemed to be the root cause of my earlier problem. Anyway so i install hentoolbox Then I rebooted I think... The tool box now says hen update has disabled hentoolbox so I go into the UI of the toolbox and reenable it that restarts the console like it should I think... but after HEN will not enable hard locks until I reset it. the only way I have found To get it to work is buy enabling HEN through the web browser Seemed ok but now like you said it is just gone...