because I confused in step 2 I write this comment:
for installing following this instruction step by step:
download PDFlib-Lite-X.X.XpX form first post...
open terminal and type:
$ cd download folder...
$ sudo tar -xzvf PDFlib-Lite-X.X.XpX.tar.gz
# cd PDFlib-Lite-X.X.XpX
# ./configure
# make
# make install
next:
# apt-get install php5-dev : online installation if not installed
# apt-get install php-pear : online installation if not installed
# pecl install pdflib : online installation
The ask be: 'path to pdflib installation? : ' enter '/usr/local'
# gedit /etc/php5/apache2/php.ini
add 'extension=pdf.so in' 1 line
# /etc/init.d/apache2 reload OR /etc/init.d/apache2 restart
Should work! for test you can write "$p = new PDF_new();" in a file.