Fedora :: Startup Fails After Update - Unresolved Dependencies

I'm currently running Fedora 13 and updated the system in the morning with the help of 'yumex'. It complained about a couple of unresolved dependencies regarding new kernel and kmod-nvidia, so I manually skipped these packages for now (this happened before some time ago and worked then a couple of days later). I installed all other packages like firefox, thunderbird, kde, gnome pidgin etc. though.

I think I remember also to have seen some X11 stuff, but aren't quite sure (not updating often, so always getting quite a number of packages at once). The problem is that the system doesn't start any longer. The start screen shows the blue progress bar, then flickers and the system halts. I tried to start any of the last two older kernels but with the same result. When running in verbose mode I can see the following:
...
Checking for module nvidia.ko: [OK]
Enabling the nvidia driver: /etc/rc.d/init.d/functions: line 530: 1033 Segmentation fault "$@"
[FAILED]
...
There are a couple of more successful steps afterwards, but the system will never start. I tried a different runlevel by appending 'init 2' to the startup line, but wasn't able to login with any of my users. In despair I tried the link 'Updating to Fedora 13' from the boot menu, but it isn't actually offering an upgrade, but a complete re-install instead.