Unless you have installed the DVD all-in-one that's floating around out there,
you need to collect the bits which are listed in the "step by step" sticky in
this forum, not all of which come from moddb.com. The basepack comes from
openplanesim.com, as the sticky link shows. If you find you are missing a plane,
it does take a bit of digging to figure out where it should be coming from.
But the openplanesim links I gave you in the previous post should get you
sorted as what comes from where. It's mostly the BasePack which has multiple .par
files in it, which Argon has listed for you.