You need to use BlackBerry desktop software for mac. If you intend to tether, then you'll need to do it that way. Bluetooth connections like that just won't work on a mac.
Mobile hotspot will if you have the BlackBerry OS 7.1 Software running on your curve, then you can tether with ease.
Typed using my BlackBerry Bold 9900 using Tapatalk for BlackBerry 7.1