yes, CentOS 6.x is very outdated, but there's a very special software that doesn't works on a newer OS.
thanks, "yum install epel-release" solved some of my problems
the other side of the problem is that i'm generally using Windows, so command-line interface is a bit challenging for me.
all these funny things like installing a virtual PDF printer via text browser is kinda unique experience for me, but that's Ok, i got Incron to work properly.