Problems uploading to board

I am trying to test TFT touch screen on Arduino Uno board, it repeatedly show uploading problems.
The error report is as below:

Arduino: 1.6.4 (Mac OS X), Board: "Arduino Uno"

Build options changed, rebuilding all

Sketch uses 20,152 bytes (62%) of program storage space. Maximum is 32,256 bytes.
Global variables use 607 bytes (29%) of dynamic memory, leaving 1,441 bytes for local variables. Maximum is 2,048 bytes.
avrdude: ser_open(): can't open device "/dev/cu.usbmodem1411": Device not configured
ioctl("TIOCMGET"): Inappropriate ioctl for device
Problem uploading to board. See for suggestions.

This report would have more information with
"Show verbose output during compilation"
enabled in File > Preferences.

The screen is on with white background

The board is "Arduino Uno"
The port is "/dev/cu.usbmodem1411"

Could anyone help me to figure it out what the problem is?

Thanks so much!!!!