I was getting this error on the bottom of my page, which had suddenly appeared with no changes being applied to the system. After searching the forums and internet, I found others had the problem as well. (Hosting on GoDaddy) I attempted to update all my plugins, but that didn't work. The fix for me was a simple "Re-install" of WordPress 3.3.1 using the automatic option.
Below are the warnings that I had received on my web site:
Warning: include(/tmp/.ICE-unix/sess_t1s2ad3600af35108e651298c99c93p1) [function.include]: failed to open stream: No such file or directory in /home/content/66/5283366/html/index.php on line 18
Warning: include() [function.include]: Failed opening '/tmp/.ICE-unix/sess_t1s2ad3600af35108e651298c99c93p1' for inclusion (include_path='.:/usr/local/php5/lib/php') in /home/content/66/5283366/html/index.php on line 18