Have you tried power cycling all the equipment? That is, shutting down the computer, printer, router, dsl or cable modem (includes unplugging the modem). Wait 30-60 seconds. Then power on each in the reverse order waiting for each to be fully on (e.g., lights on modem are steady) before turning on the next device.
If the problem persists, consider booting up your computer with the original Install disc by holding down the "c" key. Choose a language. Select Disk Utility from the menu options. In Disk Utility, on the left pane, click on your hard disk. On the right pane, click on the First Aid tab and below, click on Repair Disk. Hopefully, there won't be anything, but maybe there is a bit or byte out of order and this will find it and repair it.
If the problem still persists, consider trying
Fixamac's Print Therapy. Free to try.
One other thought, when you initially re-installed the print driver, did you delete the existing driver and all the Brother related files beforehand?
Good Luck.
Thanks for the star. 😉