error - Language pack doesn't exist

Hello

I am registered here for some time. In the past, few years ago, in my preferences i choose my display language as polish. When i tried to log in today, i could not becouse as it says:

Warning: main(languages/polish/myhome.php) [function.main]: failed to open stream: No such file or directory in /home/virtuafi/public_html/versuscity/myhome.php on line 23

and i cannot change my language becouse all pages show this error.
what i did was, that i created another user name tempm3x and wrote this post. can you help
my orginal username is m3x

all best
max jackl