Cant use IDE on GNU/Linux

Hello all! I seem to have run across a problem that is making it to where im not able to upload sketches to my board, or open the serial monitor. I followed the installation instructions "to the T", and even (i know, this was extreme) did a complete reinstall of my system. I also followed the instructions on "if you get and error saying ' Error opening serial port...", and completed them successfully using sudo usermod -a -G dialout dps, but I still get these errors.
Now, I have been able to get it to work using the terminal, and running sudo arduino (as this gives me admin privs), and from there everything works. But why is it that im not able to just double click the desktop icon, or the menu item and it work? If anyone could shed some light on the subject, it would be greatly appreciated!

dps