I am using ubuntu 12.02 32bit and have installed hadoop2.2.0 and pig 0.12 successfully. Hadoop runs properly on my system.
However,
just building with command "ant clean jar-all -Dhadoopversion=23" is not enough if you are using maven dependencies in your project. You will need to install the jar created by this in your local maven repo or use this dependency (notice "classifier" tag for hadoop2) in your pom.xml
org.apache.pig
pig
h2
0.13.0