The reason u can't dl is probably b/c u aren't registered to mc. Also popsloader isn't required to run ps1 games on psp custom firmware. It just allows you to choose which pops version you want to run your ps1 games under. Some ps1 games ran better on older psp versions for some reason.
popsloader is a CFW plugin which lets you chose what version of Popstation to load the game with. If you don't have popsloader installed, the game will load using the builtin emulator version for your firmware. The name of the emulator is Popstation. All ps1 games has to be converted to an eboot before you can play them. Tools such as PSX2PSP lets you do this in an easy manner.
I've seen a few sites mainly stockholder circlejerk blah blah sites talking about it....but ND Twitter has said nothing and Atari has been as well...I'm wondering if this is a fake story to get Atari stock up