Strange I2C Error with Arduino Nano


I'm currently building my own MultiWii Quadcopter Controlling Board. Therefore I'm reading Sensor Data from an chinese 10DOF IMU via I2C.

The board is working fine with my Arduino Duemilanove. I'm using the I2C Scanner and receiving the correct adresses (0x1E,0x68,0x77). Even reading the raw data is no problem. The connection is:
5V -> VCC
A4 -> Data
A5 -> Clock
Everything is working fine.

For the Controlling Board I am using an chinese Arduino Nano (dccduino). The connection is exactly the same but I'm getting no adresses from the I2C Scanner. It just shows:

I2C Scanner

Any ideas ?

What do you see on the scanner when you disconnect the IMU and just scan the nano. If you see the same result “Scanning”(and not the “Found 0 devices” message) there is something wrong with the nano. Likely a short between A4/A5 or one of them to ground. It may be internal to the processor(bad news)) or on the board which you may be able to find if you look carefully.

// I2C Scanner
// Written by Nick Gammon
// Date: 20th April 2011

#include <Wire.h>

void setup() {
  Serial.begin (115200);

  // Leonardo: wait for serial port to connect
  while (!Serial) 

  Serial.println ();
  Serial.println ("I2C scanner. Scanning ...");
  byte count = 0;
  for (byte i = 8; i < 120; i++)
    Wire.beginTransmission (i);
    if (Wire.endTransmission () == 0)
      Serial.print ("Found address: ");
      Serial.print (i, DEC);
      Serial.print (" (0x");
      Serial.print (i, HEX);
      Serial.println (")");
      delay (1);  // maybe unneeded?
      } // end of good response
  } // end of for loop
  Serial.println ("Done.");
  Serial.print ("Found ");
  Serial.print (count, DEC);
  Serial.println (" device(s).");
}  // end of setup

void loop() {}

Pull_ups added?