Sure you followed this part of Tom’s suggestion: “cd to your fog web directory”?
If not the command might have tried to search through all the files on your whole system. That’s not a real problem bust usually does not come to an end because it hangs when trying to read pipe files (stuff mostly sitting in /var …).
The string is found in those files:
./management/index.php:ob_start('ob_gzhandler');
./management/static/help.php:ob_start('ob_gzhandler');
./lib/fog/ProcessLogin.class.php: ob_start('ob_gzhandler');
./lib/fog/ProcessLogin.class.php: ob_start('ob_gzhandler');
See if you can fix things for you.