aruindo to read my xbee accelerometer data

Projects Networking, Protocols, and Devices
4

byte[(12)*256]+(13)] = Serial.read( ,x);

That mess has nothing to fix, it is not code.

Here is a re-write of what you were doing, kind of.

void ReadPacket( void )
  {
    if( Serial.available() >= 18 ){
      
      if (Serial.read()==0x7E ){
        
        for(int i =0 ; i< 11 ; i++) 
          Serial.read();
        
        int i_Data[ 3 ]; //3 elements for x, y, z
        
        for(int i =0 ; i< 3 ; i++)
          i_Data[ i ] = makeWord( Serial.read(), Serial.read() );
        
        /*
          i_Data[ 0 ] contains X    
          i_Data[ 1 ] contains Y 
          i_Data[ 2 ] contains Z       
        */
        Serial.print( "X: " );
        Serial.println( i_Data[ 0 ] );
        Serial.print( "Y: " );
        Serial.println( i_Data[ 1 ] );
        Serial.print( "Z: " );
        Serial.println( i_Data[ 2 ] );
      }
    }
    return;
  }

This won't help you unless you know what you were doing wrong. I suggest you read my first post and that link before you confuse yourself further.