Hello

server_default_charset = ISO-8859-1

seems to have solved the problems

That could cause problems. The Forum script, the database and the database connections are handled in UTF-8. ISO-8859-1 is a (small) part of UTF-8, but with the first special chars (like umlauts) you'll have your first problem.

Did you change the language file and saved it in ISO-8859-1? If that is the case, use a editor programm that is able to save the files in UTF-8[1]. Then you have no jumbling in the chars.

[1] Editors under Linux are generally able to save with UTF-8, under Windows you could use notepad++ for example.

Tschö, Auge