This problem seems to be trouble for a number of people.
I found the solution yesterday (while setting up a laptop with an Atheros 1091)
You need to install a specific compatibility driver.
I just posted this in another thread having to do with the same problem.
Read the page, download the patched driver bundle, follow the instructions to ONLY compile the alx driver (they are a little ways down the page).
You need the usual build tools (gcc, make, etc). You also need to have perl installed.