I believe this is what I remember, but if I am wrong and someone knows more, please feel free to correct me
The standard/default USB driver will only allow a small amount of current to flow through to the BB which will also accomodate a self-powered hub, but takes hours. The RIM driver has been customized/optimized for the BB and allows the full 500 mA of current to flow that a standard USB port can offer, but not a self-powered hub. I had the software installed but was having long charge times running through a hub and found this info on this site, switched to a direct USB port about a year ago and never looked back. I hope this helps.