I know the title is rather generic, but after I extracted the tar into the server dir, All the fields are blank and uptime shows up at NaN. There are no error messages at all. phpinfo() says that safe_mode is off (and I believe it no longer exists in the latest PHP), and it's compiled with xml support. PHP 5.3.10 with php-fpm on nginx. Linux Kernel 3.2.6 with ck patch.
I tried the older 2.5.3, but that spits out errors that none of the files in /proc exist. Specificially "common_functions.php 372 file_exists(/proc/loadavg) the file does not exist on your machine" for virtually every relevant /proc file.