Don't know what you procedure was followed to install your driver. Just to double check.. did you install the proper driver (32 or 64 bit, .deb or .rpm?) Did you take into account the required installation procedure steps?
I just download the files to my download folder and double click the file using file manager, give root password and the drivers install without a hitch.
By the way, a matter of clarification:
What I have posted is about Slackware installation; it is not relevant to other non-slack-related distros. For debian, ubuntu, mint, and relatives Brother Industries provide *.deb package, can be installed directly either by clicks or dpkg/sudo. For the rpm based --rhel, fedora, mageia, the same holds true cause Brother Industries provide *.rpm package. Neither holds true with Slackware.
Slackware uses *.tgz or *.txz packaging; and although slackware honors 'rpm -i foo.rpm' the installation goes awry against our BSD-like paths missing the libraries: slackware needs to do it 'rpm2tgz' first to correct the install script, then install it the slack way.
The OP did not mention though any hint what distro he is running: but having such trouble despite the .rpm and .deb packages available I simply surmised he could be running another, probably slackware or like sort.
Just for clarification.