I installed with new php 5.2 version on ubuntu. it was working fine. but when i tried to compile some more extension using phpize. i found errors to define $PHP_AUTOCONF and $PHP_HEADERCONF env variables. i spent about 2 hours to solve that problem and don’t want others to waste their time. just install autoconf and autoheader with the below command
aptitude install autoconf autoheader
That command will install required files at required locations and start rock with phpize :).