hmm, not sure about your second question, but for your first one - do you have a MAC address on your BCM5751? I have the same system with iDeneb 10.5.6 => 10.5.7 but I had to manually assign the IP. Reason being, because my MAC is 00:00:00... the router cannot assign IP via dhcp. Seems to go on the internet fine, but other services (AFP, UPnP) will not work without a MAC address. SMB works fine also.
I have a 8400gs 512MB (evga) installed on iDeneb v1.4 (10.5.7) and using NVInstaller v.52 worked! Here is my System Profile: Graphics/Displays: Graphics by NVIDIA: Chipset Model: Graphics by NVIDIA Type: Display Bus: PCIe PCIe Lane Width: x1 VRAM (Total): 512 MB Vendor: NVIDIA (0x10de) Device ID: 0x06e4 Revision ID: 0x00a1 ROM Revision: NVinject 0.2.1 Displays: RX326: Resolution: 1024 x 768 @ 70 Hz Depth: 32-Bit Color Core Image: Hardware Accelerated Main Display: Yes Mirror: Off Online: Yes Quartz Extreme: Supported Rotation: Supported QuartzGL: Supported Display Connector: Status: No Display Connected Thank you !!!