我想在ubuntu 12.04上安装hadoop，我的系统是32位兼容的。
我是linux新手。我试过这个教程。
我成功地完成了以下步骤：

Part 1 install Hadoop:

First, install Sun JDK 6. Go to the following page:
http://www.oracle.com/technetwork/java/javasebusiness/downloads/java-archive-downloads-javase6-419409.html

Look for x86, agree to the license, and download the file. I did this on my laptop and copied it up to the server via scp. Once it's up there follow these installation instructions:
chmod +x jdk-6u32-linux-x86.bin
./jdk-6u32-linux-x86.bin
sudo mkdir -p /usr/lib/jvm
sudo mv jdk1.6.0_32 /usr/lib/jvm/jdk1.6.0_32

sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk1.6.0_32/bin/javac 1
sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.6.0_32/bin/java 1
sudo update-alternatives --install /usr/bin/javaws javaws /usr/lib/jvm/jdk1.6.0_32/bin/javaws 1

# now we're ready to install hadoop. taken from https://ccp.cloudera.com/display/CDH4DOC/Installing+CDH4+on+a+Single+Linux+Node+in+Pseudo-distributed+Mode

# update apt to be able to access cloudera

wget http://archive.cloudera.com/cdh4/one-click-install/lucid/amd64/cdh4-repository_1.0_all.deb
sudo dpkg -i cdh4-repository_1.0_all.deb
curl -s http://archive.cloudera.com/cdh4/ubuntu/lucid/amd64/cdh/archive.key | sudo apt-key add -
sudo apt-get update

# install hadoop

sudo su
export JAVA_HOME=/usr/lib/jvm/jdk1.6.0_32/

但是，当我尝试安装“hadoop-0.20-conf-pseudo”时，出现了以下错误：

E: Unable to locate package hadoop-0.20-conf-pseudo
E: Couldn't find any package by regex 'hadoop-0.20-conf-pseudo'

你能告诉我是什么引起了这个问题吗？