Hi guys - as i thourt thi isn't a WP_multilingual problem.
Two of you send me info (thanks Rafael you relly help) about webhosts, an just one of you send me ftp access.
first that notice - in each case server return 500 error. - i thourth - well might be its a some script crashes... but not. there are two reasons to got this message
1) each of you change a directory atributes of (mo matter wp-multilingial, or plugins of wp-content dir).
for example this is http://rohvolution.ch/ site (one of you is owner) witch has wp multilingual install problems. i have change back file
atributes to drwx-xr-xr (for all inner files)
that means that server wouldn't run script if you will change atributes of dirrectory of file.
2) reason that some of you got error was at htaccess that was located at wp-multilingual folder - not its replaced.
(Options -Indexes) give error for in directory scripts.
as you see wp multilingual now enabled at site. you can download new files from this site.