/dev/ttyACM0 - No such file or directory - Arduino USB Driver NOT Loading

I'm running Ubuntu 14.04.4 and have loaded arduino through the Ubuntu Software Center. However, when I run dmesg, I'm not seeing the Arduino listed. If I run the commands rmmod cdc_acm it reports that the module hasn't been loaded. Then I run modprobe cdc_acm, it seems to load but running dmesg again, I still don't see a port named /dev/ttyACM0

I've also seen some forum entries for creating udev rules and I've used a different machine where Arduino is working to pull up the vendor id and product id. However, this solution hasn't worked for me either.

By the way, the port that shows up in the IDE is ttys0. However, when I try to upload, I get lots of errors: avrdude: stk500_getsync() attempt X of 10: not in sync: resp=0x00 avrdude: stk500_recv(): programmer is not responding

I'm using an Uno and have the board selected as Arduino Uno. I've tried all of the programmers but the avrdude messages are the same.

Any ideas on how to correct this issue and to ensure that the module is always loaded?