they are replaced by rectangles.
Is there a ways to fix this problem ?

I've a lot of French CDs with accent, I don't want to correct them one by one.

I have the same problems too, seems only US-ASCII is supported and not unicode. A solution is in the CVS-tree that would fix non US-letters in musik and moviefiles. So i guess we just have to wait for 18.2.. =)

I hope it will be fixed soon.

I don't know, but I have the feeling it won't be fix in next release.
I looked at the mailing list, and it seems the problem still occurs in 0.19.

I've created a webpage in MythWeb (mythMusic section) which make updates of DB really easier.
It looks at the musicmeta table and it looks for filenames which contains '??'. (unicode characters are replaced by ??), then it popups album, title, artist fields for all records it found.
I can edit these fields easily and click submit to apply modifications.

Now all my music is well spelled in my playlist.
I'm happy.