/ps3_home is a virtual folder - you can't see it anywhere but in multiMAN. It gathers the information for music/video/picture from your PS3 and displays it there. In other words - what you can access via XMB in Music/Video/Photo tabs.
Otherwise you must go to /dev_hdd0/music /dev_hdd0/video and /dev_hdd0/picture to access these files.
/ps3_home makes it easier to access the media on your PS3, but it is READ_ONLY at the moment. You can't copy stuff to this folder.
What I did is - I created a folder MUSIC and folder PHOTO on my internal HDD and put my images and music there.
Version 01.10.14 will be available shortly - you can update within the manager.
* Nice free type fonts added to display modes #1 and #3. Another [PATHS] mode added with [L3] (large title names, smaller title names + game path, smaller titles names without the path).
* Game scrolling is rewritten to work in PAGES and browsing is as fast as it can get for all modes.
* Fixed double listing of Blu-ray/DVD-R disc when present