I can't speak for everyone here, but for me the diagram is too hard to read for me to use it. So I have to step back and let other people help you identify the stepper issue.
Same thing with the code, you never applied code tags to it as you were asked to both 12, and 13 posts ago.
You may have a timer software collision, two libraries trying to use the same hardware timer. Consult the library documentation to find out which timers they use.
Did you just try to add code tags? It looks "blocky" like you used some different kind of tag, failed. Anyway, I want you to investigate the hardware timer usage first.
I don't do this often but here is your code, properly formatted for the forum:
#include <IRremote.h>
#include <Servo.h>
#include <Stepper.h>
int IRpin = 7; // pin for the IR sensor
IRrecv irrecv(IRpin);
decode_results results;
Servo myservo;
const int step_360 = 200;
#define STEPS 32
Stepper small_stepper(step_360, 3, 5, 4, 6);
Stepper small_stepper2(step_360, 10, 12, 11, 13);
void setup()
{
Serial.begin(9600);
small_stepper.setSpeed(60);
irrecv.enableIRIn();
myservo.attach(9);
}
void loop()
{
if (irrecv.decode(&results))
{
irrecv.resume();
}
if (results.value == 4294967295)
{
small_stepper.step(step_360);
delay(2000);
myservo.write(180);
}
}