Regarding character set mismatches, there are some comments on this page that could be helpful:

http://dev.mysql.com/doc/refman/5.1/en/charset-unicode.html

Also, the entire chapter 9.1 is about character set support. One thing that might be the issue is that character set info can be set both in the server, the database, a table, or a table field, not to mention the connection.