Hope this is still relevant a couple of months on:
Poking around /sys/block/sd* I spotted /dev/sdc/removable with "1" in (indicating removable), which is odd since there's no /dev/sdc at the time of running setup.sh
Turns out the Epson printer connected to the PC has an SD card slot which was spotted by the machine but not present. Same seems to happen wth some SD Card Readers.
The script is falling over as it's finding a reference to a drive that is empty so doesn't have a size recorded in /proc/partitions.
I see three ways to fix this:
1) Remove the SD Card Reader or Power off the printer or whatever device is presenting the SD Card slot
2) Edit setup.sh and change sd* to sdd on line 98 (assuming sdd is the USB stick you're trying to use) so that setup.sh only finds one device and works on that.
3) Someone at AVG finds another way to get the sizes of the devices and tweaks the script :-)