———- install ruby ——————–
/scripts/installruby

———- install libpcap ——————–
yum install libpcap-devel libpcap

I removed from /etc/yum.conf : ruby and perl from the exclude list
vi /etc/yum.conf

———- install rrdtool ——————–
yum install rrdtool
yum install rrdtool-devel

———- install nDPI first ——————–
cd ntop
svn co https://svn.ntop.org/svn/ntop/trunk/nDPI
cd nDPI
./configure –with-pic
make

———- then install ntop ——————–
cd ../
./autogen.sh
make
make install