Hi there,
which image do you use? please try Debian 9.4 2018-06-17 4GB SD LXQT image.
With the latest images, it should no longer be necessary to install drivers for your operating system to give you network-over-USB access to your Beagle. In case you are running an older image, an older operating system or need additional drivers for serial access to older boards, please follow step 2 of http://beagleboard.org/getting-started to install the drivers. please let us know if the issue is not solved. thanks.
best rgds
Bill