Every time I connect my ag-dvx100b to my mac pro with dual intel processor via firewire it "removes" my scratch disc, even if I boot up with them already connected. I cannot connect the camera at all and therefore can't capture footage.

Ok, well there is a workarround.. What one can do is simply use the AV cables, a USB Video IN Dongle, about $20.00. this then will allow you to connect the Camera to the PC, you can then "Stream" the Video from the Camera, to the PC, via the USB link, at FULL HD quality, save the "Played" Video as a suitable file, and do whatever you want with it. Using DVR software you simply, play on the recorder and Record on the DVR, and you'r good to go. Save as an MPEG4 or whatever format you want.
If you know how to edit the conf files then maybe you can make the existing scratch drive, persistent, making it unable to be removed.
Also you may like to try a Firewire to USB Dongle, this then will allow you to use the USB port, NOT the firewire..then at least you will be able to get data into the PC that way, although a wee bit slower, but this hardly matters in the big scheme of things.