I am using a AMD phenom chip.
Just FYI, so am I.
When I click on ports the lock file for ttyUSB0 appears.
You have probablly tried this, but I'll ask anyway: Have you tried to not click on ports (I assume you mean the menu: Tools - Serial Port), only verify that ttyUSB0 is selected, and then upload a sketch?
Btw, did you try Averageguy's suggestion?
Or how about installing the 64-bit Ubuntu? I tried that on another computer ( I was a bit "cautios" on my main computer, as I thought driver support etc. was better on the 32 bit one), but I have had no issues, as far as I know. Haven't tested it extensively, but Arduino IDE and ttyUSB0 works there too.