A common problem in situations where you don't have shell access, and have to upload CGI scripts and data files via FTP, is that things aren't where you think they are when the script executes.

One brute-force way of determining what is there is to upload a test CGI that does

    use Cwd;
    print "Content-type: text/plain\n\n";
    print getcwd(), "\n\n";
    opendir(DIR, ".") or die ".: $!";
    print join("\n", readdir(DIR)), "\n";
    closedir(DIR);
[download]

The will tell you where the script thinks it is when executing, and what else is there. You may find that you need to either chdir() or use an absolute path to open data files that reside elsewhere.