This error message is wrong. sorry for that, should be "error while reading from cache".
This means, that the script is not able to read from the cache. Normally, if it wouldn't be able to create the cache you would have get an error message "Could not create Cache file. Make sure the directory is writable (CHMOD 777)".
If this isn't the case, please check if there's a file named "cache.txt" within the same folder where you located the racers_online.php.
If there is NO file, check that the directory is writable (CHMOD 777).
Otherwise please locate the file and open it. Is it large or are there only some words written? It could be possible, that you have entered a wrong LFS Stats Ident Key and you get only an LFSW error within that cache file.
So check out what's in there and post it