The latest LTS Xubuntu 14.04 appears to present many users of Brother scanners a problem in getting set up. This is what I did to get mine working. This relates in particular to the brscan2 driver models.
Ensure xsane and sane-utils are installed
sudo apt-get install xsane sane-utils
Download the scanner driver from Brother
From the terminal enter the following instructions
sudo dpkg -i --force-all <scanner driver deb>
dpkg -l | grep Brother #checks driver installed
(for network scanner:)
sudo brsaneconfig2 -a name=SCANNER model=DCP-540CN ip=xxx.xxx.x.x
sudo brssaneconfig2 -q | grep SCANNER (checks setup)
Open up a root Thunar
copy everything from /usr/lib64/sane to /usr/lib/sane
copy everything (not folders just files) from /usr/lib64 to /usr/lib
overwrite anything that is there already.
Test scan with xsane or Simple Scan