Problem uploading to the board

Hi there! I have an issue uploading my code to the arduino board.

I'm an os x yosemite 10.10.2 user and the board i'm using is an arduino UNO. I had been able to upload the code sometimes, but other times when I try to upload the code the connection is out and it returns this error message:

Arduino:1.6.3 (Mac OS X), Placa:"Arduino Uno"

Sketch uses 2.306 bytes (7%) of program storage space. Maximum is 32.256 bytes.
Global variables use 54 bytes (2%) of dynamic memory, leaving 1.994 bytes for local variables. Maximum is 2.048 bytes.
avrdude: ser_open(): can't open device "/dev/tty.usbmodem1411": No such file or directory
ioctl("TIOCMGET"): Inappropriate ioctl for device
Problema subiendo a la placa. Visita http://www.arduino.cc/en/Guide/Troubleshooting#upload para sugerencias.

can anyone help me?

sorry if my message is not so correct, I'm new in the forum, still don't know how the things work correctly here