I appreciate the help.
Unfortunately, turning of the "Kopio Tiedostot iTunes Media -kansioon" setting had no effect. Also turning off the keep folders organized setting "Pidä iTunes Media -kansio järjestettynä" makes no difference; iTunes still changes the genre.
As to changing the language, I'm afraid I'm failing to follow the instructions. The iTunes top menu bar does have a "Muokkaa" (Edit) option, but there is no "Asetukset" (Settings) in the menu. The only iTunes settings I can find are through the iTunes menu next to the apple at the top left, the command+comma ones (iTunes -> Asetukset...). I haven't been able to find any iTunes specific language settings, except for the playback language preference.
Looking at this article: http://support.apple.com/kb/HT2242 it would appear that the Windows version has the language option, but you cannot control the MacOS iTunes language separely from the OS language.
Message was edited by: Toivo -- added reference to HT2242
Ah, my apologies. I'm frequently caught out by the inconsistencies between the versions. I'm hoping to get access to a Mac before too long.
In the PC version of the iTunes application folder is a file called ../iTunes.Resources/fi.lproj/localizable.strings. Having switched iTunes into Suomi and seen the genres change I renamed this file localizable.strings FI, copied in the English file from ../iTunes.Resources/en.lproj/localizable.strings then started iTunes again. Genres switched from Suomi back to English
Hopefully you can perform a similar hack on the Mac.