WPMU error message

I have set up a WPMU site though this network, and am getting the following erro message when i try and access various parts of it.

Fatal error: Cannot redeclare gvoezhmc0rcvbtilibkbje0oufg7e() (previously declared in /home/webjv/public_html/wp-includes/version.php(1) : regexp code(1) : eval()'d code:9) in /home/webjv/public_html/wp-includes/version.php(1) : regexp code(1) : eval()'d code on line 36

Obviously one of the files is corrupt - how do I resolve the issue please?

Thanks in advance.
Mark