i don't know where else to advise you except at installing the script...
like i said, after Installing Core Packages, it should be a breeze from there on. And i never had any problems with setting permissions, so i can't help you on this one. perhaps you put ps3 passwd with Caps enabled or something...
edit: just in case you have any problems, on the script always set the username and password to ps3 and BE SURE that caps isn't enabled or something else like that (problems with numpad/numlock)
edit 2: yup, script installed fine, no problems, had to run it on the second time to make it work. it seems that the cpu works better on 3.41 otheros++ than on 3.55, not sure though. anyways, after installing, enter, and type
sudo apt-get install gdm3
to get the Desktop environment and all the minimal things to it.
in case you want to run glevand's latest kernel, go get it:
tar -xvf linux-3.3.4-build.tar.bz2
sudo cp -R * /
and add the following line to kboot.conf as root
"Whoever has ears, let them hear."