Restoring Home directory after booting live CD

[Chanchao]

Hi,

On my office computer I would like to run Ubuntu, but currently I
can't install it there for various reasons.

I used the Live CD for a while, and can configure some settings pretty
quickly now, and if I basically never turn the thing off then I keep my
settings..  yet... sometimes I just have to restart, or boot up
windows for some reason, then I have to start from scratch again. :(

So I backed up my home folder to a USB pendrive, using tar.  (% tar -cvf
/media/pendrive/ubuntu.tar ubuntu )  To be sure I did this while out
of all applications, I even quit gdm and did it from the command
prompt. This way I hoped all my settings, including gnome settings,
firefox stuff, openoffice templates, etc, etc would be properly backed
up.

HOWEVER, when I restart, boot from CD and then put the stuff back (tar
-xvf /media/pendrive/ubuntu.tar)  then gnome refuses to start, I get a
failsafe xterm instead.  When I start all the way into gnome first and
then restore the home folder then nothing works anymore; applications
simply fail to start up.

I checked permissions and it seems to be correct, the user and group
are 'ubuntu'.  Also I'm doing both the backing up and restoring while
logged in as 'ubuntu', not sudo or root or anything.

What am I doing wrong?  It would be so nice to have my own Ubuntu
installation with my own settigns that I can just run on any computer.
(Already tried DSL and Puppy but found them too limited: I like the
functionality Ubuntu provides and need OpenOffice as well as the
kitchen sink. :)

Toughts, suggestions?

Cheers,
Chanchao