Comment 27 for bug 719446

Looks like the effects of apt being interrupted while it was doing something before. It shouldn't matter for kernel compilation, but you may want to uninstall and reinstall VirtualBox at some point (which should fix the error). You do need the build-dep linux though, so if the error occured before the installation finished, then there's a (very small) chance that you can get some really weird errors when you attempt to compile the kernel if you don't fix it.

The first two warnings from update-rc.d don't really mean anything bad, it apparently is a configuration bug in Ubuntu ( https://bugs.launchpad.net/ubuntu/+source/kexec-tools/+bug/569980 ) - kdump is used to create kernel crashdumps and all this is saying is that they will only be created during 'normal operation' (runlevel 2) rather than also during startup, shutdown, etc (which have different runlevels).