I also have a Dell Vostro 1510 with the RTL8111/6168B and I have the same problem too. I tried to use acpi=off or pci=nomsi as boot parameters (with 2.6.27-7 and 2.6.27-9) but it didn't seem to change anything. The network stays unavailable either using the Network Manager either disabling it completely. In the last case, you can still get an eth0 up, put an IP to it (module r6169 is loaded, eth0 appears) but nothing more (no ping, etc...).
I also have a Dell Vostro 1510 with the RTL8111/6168B and I have the same problem too. I tried to use acpi=off or pci=nomsi as boot parameters (with 2.6.27-7 and 2.6.27-9) but it didn't seem to change anything. The network stays unavailable either using the Network Manager either disabling it completely. In the last case, you can still get an eth0 up, put an IP to it (module r6169 is loaded, eth0 appears) but nothing more (no ping, etc...).