CHAS90  I have a 10.4.11 Intel Mac, and iPaint is running on it.

But that's just because I denied every further update after version 1.4. (The newer versions all produced the same problems as for the other users)

In this version the only things that don't work are: cutting and copy&pasting... and I have to forcequit.  
(Version 2.0)

CHAS90  I have the same problem as Paul Mellor.

I then downloaded it again and told him NOT to update. Version 1.1 is running smoothly.

I have a Intel 10.4.11...  
(Version 1.4)

CHAS90  I wanted to suggest that you add another learning mode where you have to think the other way round: So that Nuku asks for the syllable 'to', for example, and you have to find the hiragana/katakana と/ト in the list...

That way, the software would be more effectiv^^  
(Version 1.5.1)

CHAS90  Well, I try to open the programm, the icon bounces in the dock for a second or so, and then disappears.

It doesn't work; I've tried several times...  
(Version 2.5.7)