As written in the PDFreactor Software License Agreement a PDFreactor license can only be used on 1 (one) physical or virtual machine in an Intranet/Extranet, or over an Internet installation with non-anonymous or anonymous users. So, if you have various physical or virtual machines/servers you have to purchase separate PDFreactor licenses, which cover the appropriate number of CPUs of each virtual machine/server. You are not allowed to purchase the required cumulative number of PDFreactor License Packs in form of one single license and install the license key on each virtual machine/server.