Libraries not working together

so i have two libraries in this project, DMX Library for Arduino and Stepper, but when I try to compile, I get this error message:

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 Uno.

I'm guessing they are both trying to use a serial port, but I'm not sure how to fix it. can anyone help?? For reference, heres the code:

#include <Rdm_Defines.h>
#include <Rdm_Uid.h>
#include <Conceptinetics.h>

#include <Stepper.h>

// setting number of channels
#define DMX_SLAVE_CHANNELS 10
DMX_Slave dmx_slave ( DMX_SLAVE_CHANNELS );

#define STEPS 200
// my hybrid has 200 steps/rev

// initialize the stepper library on pins 8 through 11:
Stepper stepper(STEPS, 8, 9, 10, 11);
int previous = 0;

void setup() {

// Enable DMX slave interface and start recording
// DMX data
dmx_slave.enable ();

// Set start address to 1, this is also the default setting
// You can change this address at any time during the program
dmx_slave.setStartAddress (1);

// set the speed at 60 rpm:
stepper.setSpeed(60);
// initialize the serial port:
Serial.begin(9600);

}

void loop() {

// If the first channel comes above 50% the led will switch on
// and below 50% the led will be turned off
int cha1 = dmx_slave.getChannelValue (1);

stepper.step(cha1 - previous);

previous = cha1;

}

I'm guessing they are both trying to use a serial port, but I'm not sure how to fix it. can anyone help??

Nope, You are !

  // initialize the serial port:
  Serial.begin(9600);

The conceptinetics library clearly states that your sketch can not have any reference to the same Serial object that yo use for DMX