Nvidia kernel module not receiving interrupts from graphics device

Binary package hint: nvidia-glx

When I attempt to start x with the nvidia driver, x fails to start with the error message:

(EE) NVIDIA(0): The NVIDIA kernel module does not appear to be receiving
(EE) NVIDIA(0): interrupts generated by the NVIDIA graphics device
(EE) NVIDIA(0): PCI:1:0:0. Please see Chapter 5: Common Problems in the
(EE) NVIDIA(0): README for additional information.
(EE) NVIDIA(0): Failed to initialize the NVIDIA graphics device!

Previously, I also had a problem on this computer where it couldn't find the nvidia kernel module. This problem is resolved now -- I believe that this was fixed somehow when I installed linux-restricted-modules-generic, even though I'm actually using the -386 kernel. Previously there was no nvidia.ko in /lib/modules/2.6.20-13-386/volatile/, now there is. (I don't really know the reason why.)