uploading error: programmer is not responding

Hello, I have put together the Gamer Kit, when I connect the ARDUINO, on its own, it can upload but as soon as I put the whole thing together with the upper part , it cannot upload and I get the following error messages. Please help! Thanks

Arduino: 1.8.1 (Mac OS X), Board: "Arduino/Genuino Uno"

Sketch uses 1968 bytes (6%) of program storage space. Maximum is 32256 bytes. Global variables use 151 bytes (7%) of dynamic memory, leaving 1897 bytes for local variables. Maximum is 2048 bytes. avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x00 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x00 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x00 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x00 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x00 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x00 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x00 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x00 avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x00 Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.

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

I meant when I attach the upper part (the LED Matrix) I get the error message above

That would indicate that the board you are attaching to your Arduino uses the TX and RX pins that are needed for USB communications.

Simply remove the shield…upload…re attach shield.

Or break into the lines and fit a switch.
Maybe it has a jumper os something.
Pretty hard to tell from here without more info.