Check the USB spec. Maximum for USB2.0 is 5 meters; you're exceeding that and hence all bets are off.
My suggestion would be to use RS232.
If you want to do uploads over that distance, don't forget that you need GND, RX, TX and DTR. You will need to power your Arduino with a separate power supply.
Your topic has been moved to a more suitable location on the forum. Installation and Troubleshooting is not for problems with (nor for advice on) your project 
See About the Installation & Troubleshooting category.