Opencart: open_basedir restriction in effect

Hi everybody, I am new, I just installed OpenCart few days ago for the first time, so please have patience with me

I made some changes at css, tpl and also php files in order to customize OpenCart 1.5.0.4. All worked well right after changes. But next day (today), all I got is this message instead of working eshop at http://www.vymazlena.cz/ :

Warning: require_once(): open_basedir restriction in effect. File(/data/www/www_vymazlena_cz/www/system/startup.php) is not within the allowed path(s): (/data/www/www_vymazlena_cz/vymazlena_cz) in /data/www/www_vymazlena_cz/vymazlena_cz/www/index.php on line 15 Warning: require_once(/data/www/www_vymazlena_cz/www/system/startup.php): failed to open stream: Operation not permitted in /data/www/www_vymazlena_cz/vymazlena_cz/www/index.php on line 15 Fatal error: require_once(): Failed opening required '/data/www/www_vymazlena_cz/www/system/startup.php' (include_path='.:/usr/local/share/pear') in /data/www/www_vymazlena_cz/vymazlena_cz/www/index.php on line 15

Have you any idea what happened? I dont want loose all the job I already done there...it took several days....
I will appreciate any help.

Antares

I already figured the reason - during the night my hosting was changed at multihosting....structure of files changed...its not hosted at www/ but vymazlena_cz/www/..... now....any idea where I have to make these changes now?