This is what site5 said (I think the 2 IPs are because I use cloudflare. Could that be the problem?)
The error message you're seeing is because Wordpress or your WP Super Cache plugin is having trouble determining if the 1.html or 2.html file are identical with the same timestamp. I have confirmed that they are identical as you can see here:
root@lawfirm911 [/home/lawfirm9/public_html/wp-content/cache]# ls -la 1.html
-rw-r--r-- 1 lawfirm9 lawfirm9 16056 Jun 11 22:13 1.html
root@lawfirm911 [/home/lawfirm9/public_html/wp-content/cache]# ls -la 2.html
-rw-r--r-- 1 lawfirm9 lawfirm9 16056 Jun 11 22:13 2.html
root@lawfirm911 [/home/lawfirm9/public_html/wp-content/cache]# md5sum 1.html 2.html
fa3718a117dc60978b4e3cfcaa3e3884 1.html
fa3718a117dc60978b4e3cfcaa3e3884 2.html
While performing local tests I can see that any query to grab the 1.html or 2.html file ends with a 404 error so this could just be a false positive:
lawfirm9@lawfirm911.com [~/tmp]# wget http://lawfirm911.com/1.html
--2012-06-11 22:23:40-- http://lawfirm911.com/1.html
Resolving lawfirm911.com... 108.162.196.198, 108.162.193.100
Connecting to lawfirm911.com|108.162.196.198|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2012-06-11 22:23:41 ERROR 404: Not Found.
lawfirm9@lawfirm911.com [~/tmp]# wget http://lawfirm911.com/2.html
--2012-06-11 22:23:43-- http://lawfirm911.com/2.html
Resolving lawfirm911.com... 108.162.196.198, 108.162.193.100
Connecting to lawfirm911.com|108.162.196.198|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2012-06-11 22:23:43 ERROR 404: Not Found.
As long as your caching plugin is currently working I would write this off as a test failure. The server itself is resolving the correct IP address as you can see here:
lawfirm9@lawfirm911.com [~/tmp]# dig lawfirm911.com +short
108.162.196.198
108.162.193.100
However I see that there are two IP addresses that appear which may or may not be intentional. This could affect the way your caching test operates locally on the server.