Regarding not recognizing files and folders with underscores in them...
Sharp's File Open widget does that. No way to fix that other than using some other widget. Same problem with files, which have period in their name.
This doesn't sound right. The Zaurus comes with directories named Book_Files, Image_Files, Install_Files, etc.; I can navigate through all of these in PortaBase, which uses the file navigation widget from libsl. The vast majority of my PortaBase files also have underscores in their names (Domestic_anime_DVDs.pob, etc.), and they show up and open just fine in the same widget. I haven't had a chance to look at the latest kino2 build yet, but if it's having problems with these kinds of names it should be fixable.
Now files with periods in their names are likely to be a problem; Qtopia strips off file extensions, and having extra periods in there confuses this mechanism. Case in point, Sharp's "new file" dialog won't even let you enter a period. But underscores are allowed in this dialog, as that's how I created the aforementioned PortaBase files.
Am I just misunderstanding the problem? I've been looking forward to trying out the latest version of kino2 (since 0.4 wouldn't run on my Zaurus), but since I do most of my file management from a Linux command line, I generally use underscores instead of spaces in all my filenames; a bug like this would force me to rename pretty much all media files I move to the Zaurus.