Cannot find USB Blaster

I am running Red Hat Enterprise Linux 6 64bit. I have followed the instructions here:

http://www.altera.com/download/drive...usb_b-lnx.html

I have set the QUARTUS_ROOTDIR path like this:

export QUARTUS_ROOTDIR=/root/altera/13.0/qprogrammer

Yet, I still get this error when browsing for the USB blaster

"Error: QUARTUS_ROOTDIR is not set"


What else can I try?

Thanks.