Actually, the program you need to download from that site is the setup for the English version of PAF 5.2 (Personal Ancestral File).
PAF Companion is a printing utility that can open PAF files and print charts. (The free basic/trial version is very limited.) The unlock codes cost $6.75 USD (the last time I checked), and give you access to all of the charts that this product can print. But it opens the PAF files in a read-only mode, you cannot add or edit data.
PAF is the software that you need. It will allow you to edit your data files, create new data files, import and export data, etc. It also has some charts and books you can print from your data, just not as many different charts as PAF Companion can print.
If you have difficulty installing PAF, you may need to uninstall your current installation of PAF 5.2.