1 - There seems to be a problem with the .bz2 dump
file wikipedia
provides. I tried to download it twice, and it aborted on an error after
running for about 7 hours, at about 2GB.
Generally speaking, the answer to a problem like that is usually in
the error message (although not always in a language human beings can
understand, so if you don't understand the message, email it to this
list and someone might be able to help).