To transfer files via FireWire, you have two choices. Target Disk Mode will basically turn your computer into an external hard drive over FireWire/Thunderbolt. To use that properly, I would put your Mac Pro into Target Disk Mode (hold T at startup), and the drive(s) from that computer will mount on the desktop of your MBP.
You can also instead use IP-over-FireWire. To do that, go into System Preferences on each Mac, open Network, and add a new interface (the plus button at the bottom left). From the Interface drop-down, choose FireWire (you should have the adaptor plugged into your MBP when you do this, and it may say Thunderbolt-FireWire adaptor or something similar). Then, your computers will connect to each other over FireWire via file sharing, and should appear in the sidebar in the Finder. Only trick is if there is another network connection available which has priority over FireWire, it will default to that. To fix that, click the gear icon in Network Preferences, choose Set Service Order
, and move FireWire to the top of the list.
jW