Trevor Richardson wrote (...) I started like you then adapted :-)
so, first on the source computer
mysqldump -p wikidb > wikidb.sql
for me I nedded to do this as root. then option -p made mysqladmin to call for the passwd (root mysql pass) (linux, no "exe")
tar cvfz med_158.tgz mediawiki/
to have all the old files.
then on the target computer:
mysql -p and mysql opens it's console use wikidb source wikidb.sql
but one must start from a clean mysql (no wikidb before, or delete it)
tar xfvz med_158.tgz
test: it should work. same mediawiki site but on the new computer.
then overwrite the folder with the new 1.6.3 files, in the mediawiki root folder cp AdminSettings.exampl to AdminSettings.php and in it replace wikiuser by root and set it passwd
run maintenance/update.php
and enjoy the new mediawiki 1.6.3
in fact I missed at first the Admi.. stuff
thanks all
jdd