Cannot create new content 3.1.4

From Joomla! Documentation

Some users report that they receive the following error when attempting to create new content (of any type).

Errors reported

HTTP Error 500 (Internal Server Error): An unexpected condition was 
encountered while the server was attempting to fulfill the request.

or with maximum reporting on

Fatal error: Invalid opcode 153/1/8. in 
/var/.../libraries/joomla/table/observer/tags.php on line 159

Versions affected

Info non-talk.png
General Information

This pertains only to Joomla! version(s):- 3.1.4

What is the cause

This appears to be caused by a bug in eAccelerator.

How to fix

Either update to the current Joomla! version or change your caching method to a different option.