Recompiled Ubuntu kernel - nvidia driver does not load (comm: modprobe Not tainted)

Binary package hint: nvidia-new-kernel-source

I recompiled the Ubuntu kernel from source 2.6.24-15.27 together with alsa-source 1.0.16-0ubuntu4 and nvidia-new-kernel-source 169.12+2.6.24.12-15.33 and created Debian packages from them to install them. This kernel boots well except of one detail - it does not load the 'nvidia' driver as the default kernel does.

I used the original kernel configuration from Ubuntu, except the processor family settings, which I changed to Core 2 / Xeon or newer and symmetric multiprocessing, nothing else. After unpacking all 3 sources and configuring the kernel I compile it and produce the deb packages this way (in a script):
CONCURRENCY_LEVEL=3 MAKEFLAGS="CC=gcc-snapshot" fakeroot make-kpkg --initrd --revision "$2" kernel_image kernel_headers modules modules_image

I tried even renaming the new kernel module nvidia -> nvidia_new.ko after installing it, but this is not the point, so this is NOT a duplicate of #107368 (https://bugs.launchpad.net/ubuntu/+source/linux-restricted-modules-2.6.20/+bug/107368)

In /var/log/messages I get the following:
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Apr 9 10:42:12 charlie kernel: [ 53.100917] Pid: 3087, comm: modprobe Not tainted 2.6.24.3 #1
Apr 9 10:42:12 charlie kernel: [ 53.100918]
Apr 9 10:42:12 charlie kernel: [ 53.100919] Call Trace:
Apr 9 10:42:12 charlie kernel: [ 53.100935] [sysfs_add_one+0xdf/0x120] sysfs_add_one+0xdf/0x120
Apr 9 10:42:12 charlie kernel: [ 53.100938] [create_dir+0x60/0xc0] create_dir+0x60/0xc0
Apr 9 10:42:12 charlie kernel: [ 53.100944] [sysfs_create_dir+0x31/0x50] sysfs_create_dir+0x31/0x50
Apr 9 10:42:12 charlie kernel: [ 53.100947] [kobject_get+0x12/0x20] kobject_get+0x12/0x20
Apr 9 10:42:12 charlie kernel: [ 53.100950] [kobject_add+0xb3/0x210] kobject_add+0xb3/0x210
Apr 9 10:42:12 charlie kernel: [ 53.100954] [pci_hotplug:kobject_register+0x28/0x3470] kobject_register+0x28/0x50
Apr 9 10:42:12 charlie kernel: [ 53.100959] [bus_add_driver+0x89/0x230] bus_add_driver+0x89/0x230
Apr 9 10:42:12 charlie kernel: [ 53.100964] [sys_init_module+0x198/0x1aa0] sys_init_module+0x198/0x1aa0
Apr 9 10:42:12 charlie kernel: [ 53.100972] [__up_write+0x21/0x150] __up_write+0x21/0x150
Apr 9 10:42:12 charlie kernel: [ 53.100980] [system_call+0x7e/0x83] system_call+0x7e/0x83
Apr 9 10:42:12 charlie kernel: [ 53.100987]
Apr 9 10:42:12 charlie kernel: [ 53.100992] Pid: 3087, comm: modprobe Not tainted 2.6.24.3 #1
Apr 9 10:42:12 charlie kernel: [ 53.100993]
Apr 9 10:42:12 charlie kernel: [ 53.100994] Call Trace:
Apr 9 10:42:12 charlie kernel: [ 53.100997] [kobject_add+0x149/0x210] kobject_add+0x149/0x210
Apr 9 10:42:12 charlie kernel: [ 53.101001] [pci_hotplug:kobject_register+0x28/0x3470] kobject_register+0x28/0x50
Apr 9 10:42:12 charlie kernel: [ 53.101005] [bus_add_driver+0x89/0x230] bus_add_driver+0x89/0x230
Apr 9 10:42:12 charlie kernel: [ 53.101009] [sys_init_module+0x198/0x1aa0] sys_init_module+0x198/0x1aa0
Apr 9 10:42:12 charlie kernel: [ 53.101017] [__up_write+0x21/0x150] __up_write+0x21/0x150
Apr 9 10:42:12 charlie kernel: [ 53.101024] [system_call+0x7e/0x83] system_call+0x7e/0x83
Apr 9 10:42:12 charlie kernel: [ 53.101030]
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I'm not sure whether this is a bug or whether I do something wrong, but I cannot find any useful hint.

René