I download the Ditty importer by EA SPORTS and the fifa 2000 webmaster says it was made for NHL 2000 but also works for FIFA 2000. and i cant convert files to .str filetypes. I can only convert them to .asf which is not a fifa 2000 music file. does anyone know how to convert to .str

Just rename it from ASF to STR in DOS or Windows Explorer. If you wish to do it VIA Widnows Explorer remember to take the hide known file types endings off in the options, View menu.