This is not a problem with Wordpress - It's a problem with the way your hosting company has their server set up. The first (and biggest) clue is that Wordpress doesn't use any encoded files, so that error made no sense for a standard install.
From what I've read up about that error message, it's coming from a PHP component called APC. That needs to be disabled on the hosting server by commenting it out in the php.ini file that the server uses:
#extension=apc.so
Now, unless you're running your own server, you'll need to contact your hosting company and ask them to fix this for you.