Yah you need to install Pocket Mac, that should solve it.

The issue is that a BlackBerry relies upon a piece of software (the Windows driver, for instance) to detect when a BB is plugged in and dynamically adjust the USB current on that port from 100mA to 500mA. On Windows this is the Device Manager install portion (which installs the driver), a Mac needs Pocket Mac, and linux now has 'bcharge' (there is also a new kernel module 'berry_charge' in the upcoming 2.6.21 release.)