Welcome to My Dell Mini.
That is an old guide and it is lacking one very important instruction.
It says to reboot after OS X has completed installing. This is incorrect.
Immediately after OS X has finished installing on your mini, when it gives you the reboot countdown, you should go to the menu bar at the top of the screen and select Utilities and run NetBookInstaller with the default selections that are already checked off. This loads the boot loader, and all the kexts required to allow the track pad, video, and wifi to work properly.
NBI should be in your mini's Applications folder as well, and you can run it from within OS X as well. This should fix your issues.
Mini 9 | OS X 10.6.7 | NBI 20100616212351| BIOS 05 | 32 GB Runcore | 2 GIGS RAM
10V | OS X 10.6.7 | NBI 20100616212351 |BIOS 06|160 GB|1 GIG RAM| 6 Cell Dell Battery
Functioning Hibernation
Back up Mini 9| OS X 10.6.7| NBI 20100616212351| BIOS 05 | 32 GB SuperTalent | 2 GIGS RAM