Hi Harlan,
Not sure why updating the Activdriver resolved the issue for some teachers and not others. Try disconnecting all Promethean hardware from the computer and go to Applications > Promethean > ActivDriver > Uninstall
Restart the computer and run a repair on disk permissions.
To do this select Applications > Utilities > Disk Utility > Mac HD > First Aid > Repair Disk Permissions
Once the repair is complete, restart the computer and re-install the driver.
To download the file(s) please click on the respective link(s) below.
Save/ Install the driver link below.
Your password is: 9rSt5PyJ
Name: ActivDriver v5.9.16.dmg
Size: 48.10 MB
Expires: November 17, 2013
Once the ActivDriver is installed, reconnect all Promethean hardware. (case# 286710)
Hope this helps!