It is a well known bug. Look at https://bugs.launchpad.net/ubuntu/+s...x/+bug/1030858

I use an wireless LAN adapter by Edimax with the same chipset. In post #73 of the thread mentioned above you will find a link for the latest Linux driver. If you are curious you can install this driver and boot up your system using the additional cheat code 'modprobe.blacklist=rtl8192cu'.