Error using DMX lib with Firmata - multiple definition of `___vector_18'

Hi. I need to use Firmata so I can control DMX from Flash. MY DMX library tests alone work, but when i include Firmata, using the standard library in Arduino Uno, I get this when I compile:

HardwareSerial0.cpp.o (symbol from plugin): In function `Serial':
(.text+0x0): multiple definition of `__vector_18'
libraries/Conceptinetics/Conceptinetics.cpp.o (symbol from plugin):(.text+0x0): first defined here
collect2: error: ld returned 1 exit status
exit status 1
Error compiling for board Arduino/Genuino Uno.

I have seen other examples of this kind of error on the forum but not relating to Firmata and the particular HardwareSerial0.cpp file, so unsure how to solve it. Any thoughts, please?

This is what my includes look like:

#include <Boards.h>
#include <Firmata.h>
#include <FirmataConstants.h>
#include <FirmataDefines.h>
#include <FirmataMarshaller.h>
#include <FirmataParser.h>

#include <Conceptinetics.h>
#include <SimpleTimer.h>