Technically you're not doing anything wrong, that file does belong in the componentpeds.img, but the problem is that the mod replaces a certain civilian (not Niko). Componentpeds.img has all the pedestrian models in it , playerped.rpf is for Niko. So when installing a mod that replaces files in componentpeds.img you're replacing a pedestrian.
About OpenIV, it just skips the 'pc' folder so you can go straight to models/cdimages. But I recommend using SparkIV if you're new to this because it'll tell you if the file doesn't exist (so you know you're in the wrong image).
If you still want to change into that person you could try simple native trainer, first make sure you have your game updated to the latest patch (22.214.171.124.) or the one before that (126.96.36.199.)
Then just drop these files in your main folder (Usually program files(x86)/Rockstar Games/Grand theft auto 4): http://www.mediafire.com/?mkd87cns1jr85cu
I uploaded that package myself and it has all the required files for the trainer (and you won't need to install any extra files when installing your next script mod). It does have an asiloader aswel (dsound.dll) since you already have xliveless.dll you can either just not install dsound or remove xliveless (removing xliveless will re-enable the GFWL interface).
Now when you've installed it just hit F3 (ingame) and browse to 'model spawning' with numpad (8 is up, 2 is down and 5 is your enter button).
Then browse through that list until you find m_y_gkor_lo_02 and select that one, now you'll turn into that guy. You can keep playing as him, but I'd advice you not to try to play missions with a pedestrian. The cut-scene will most-likely freeze up. But you can free roam all you like with that model