It looks like a Nessus scan to me. First off, they're trying Linux commands on a Windows machine, so.....Secondly, halfway through the log you find http://rfi.nessus.org/rfi.txt which identifies it as a Nessus scan.

This is the contents of that file:

<?php
 # NessusFileIncludeTest
 echo base64_decode("TmVzc3VzQ29kZUV4ZWNUZXN0")."\n\n";
 echo "'id' output: ";
 system("id");
php?>