Numerous Hack Attempts

I have been using TimesToCome Security Plugin. For the last two days within minutes apart, I have been recieving entries like the one below.
How is this happening, is it some sort of logrythem designed to try every 2 minutes? Surely one person isn’t attempting to hack this site over and over right?

IP: 24.166.82.46 September 29 2009 07:47:17
Request: /wp-admin/admin-ajax.php?action=wp-compression-test&test=no&1254224831635
Code: Attempted hack
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 3.5.30729)

IP: 24.166.82.46 September 29 2009 07:47:16
Request: /wp-admin/admin-ajax.php?action=wp-compression-test&test=2&1254224830883
Code: Attempted hack
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 3.5.30729)

IP: 24.166.82.46 September 29 2009 07:47:15
Request: /wp-admin/admin-ajax.php?action=wp-compression-test&test=1&1254224830213
Code: Attempted hack
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 3.5.30729)