Issue with CodeIgniter 3.1.4

Sorry, this is my first thread, i dont know how to start with
but i got a trouble with my CI 3.1.4 version

this is the log :

Code:

Fatal error: Call to a member function getMessage() on integer in /home/xxx/system/core/Common.php on line 65
A PHP Error was encountered
Severity: Error
Message: Call to a member function getMessage() on integer
Filename: core/Common.php
Line Number: 653
Backtrace:

Did someone change the CI system files? (also, what is on line 65 in Common.php in your system folder?)

That's line 653, not 65.

_exception_handler() is being used as an error handler. Looks like a botched/incomplete update from CI2.