I've got a v1.5.0 test installation that I made as "fully" utf-8 (utf8_general_ci collation, DB_CHARSET=utf8, CHARSET=utf-8 in both catalog & admin english.php files). No plugins (yet), just a non-intrusive template add-on.

I was poking around, searching for which file(s) use the TEXT_EMAIL_MESSAGE_ADMIN_SETTINGS_CHANGED define, plugged that value into the Key or Name to Lookup in all files, Catalog/Admin, .php only, not case sensitive ... punched Search and the only file found was /MYADMIN/includes/languages/english/modules.php. Thinking that was a bit funny, I opened /MYADMIN/modules.php up in NotePad++ and there's the string (on line 72).

Has anyone else run into this? Is there some system setting (I'm running XAMPP 1.7.4 on Win7-Ultimate-64-bit) that needs changing?