Weird Web Server Issue

Ok, so a day ago we started getting some weird errors with our webserver. Sometimes, I stress sometimes, when you connect to anypage on the server you will get errors like:
http://i.imgur.com/51nJwfK.png
Again I stress this happens maybe once every ten tries doing something. We have talked with our hosting provider, A Small Orange, and they believe that the issue is that our server is running out of memory. We don't see how that is possible since the site has been running fine for several weeks now without the issues. The host then increase the memory allocation accordingly and we still get these error messages on the server. At this point we are pulling our hair out of our heads. We tried server diagnostic tools to looking for maybe a DoS attack but that was not the issue. We used tools like newrelic to see the server statistics and usage and nothing significant in changes showed up. I am going to attach a link to an image of the phpinfo information. http://westutter.org/phpinfo.png. We are running on CentOS. Here is our apache httpd.conf file http://pastebin.com/2zt1z6rK.

At this point we are looking for any and all suggestions to help us fix this annoying problem. We have even thought of asking the server company whether the storage device is failing. Any thoughts are appreciated. Thanks!

 

Have you ran a top command while you experience the load? This should tell you if you are running out of RAM. Otherwise, can you post up the error logs, if any you are getting/seeing?

 

Those errors are suggesting a particular file required is not available - if you're not seeing this error all the time, I'd check your disk i/o, especially if it is shared hosting