kde and manual change if uid and gid

[tadek@telus.net (Tadek)]

I set up small network of linux machines. I have user 'tad' with id
501 on NFS server and uset 'tad' on one of the pc with NFS client
(id=1001).  When the client is accessing mount point on the server
files appear, but there are read only, although I set them up as rw in
/etc/exports of the server.

On the client machine I changed in /etc/passwd (vipw) uid to 501.  I
changed also gid (using vigr), since 'tad' has group too.  Next I
chown -R 501:501 /home/tad on the client.  Then I tried to logout and
login again.  To my horror 'tad' disapper from the list of the user in
kde loggin.  I have no problem logging as 'tad' without starting X.

Could you please help and point what I have done wrong, short of not
setting up NIS on the server and how I can recover.

Cheers,
Tad Dragowski