[wp-testers] Unable to update my Wordpress 3.0

[Swampert]

I made a clean install on of Wordpress 3.0 beta 1(downloaded from
http://wordpress.org/nightly-builds/wordpress-latest.zip) my server.
But whenever I clicked Update Automatically, it stoped at "Downloading
update from http://wordpress.org/nightly-builds/wordpress-latest.zip…" and
there's nothing more.
There is a wordpress-latest.tmp file in wp-content but it's 0 byte size.

I could install themes and plugins directly from Internet, so this doesn't
seem to be a config/permission problem.

My server runs php 5.3.2 & Apache 2.2.14 & Mysql 5.1.41 on an Ubuntu Server,
and all files/directoris of wordpress belongs to www-data/www-data with a
777 permission.
The curl and socket functions works well.

-- 
Ilex.Swampert.
52POKE.COM - Paradise for Pokémon Fans