Hello,
Sorry to a bother but I am having trouble using custom roads. Apparently I downloaded
CuriousB 's custom road overlay, which they claim that the road cover for lot view is found under deco>misc.

But it's not there,not even the thumbnail/icon. Yes, I've downloaded everything as whole bundle yet the overlay deco doesn't come.

So I tried child of air's road overlay, and still I see no new icon. Then I tried another one from someone's blogspot (I forgot the name and the zip doesn't show Creator's name) an still no result.

The neighborhood view looks alright for all though. Only sunni's roads work as they use tiles instead (rip dear Sunni)

So am I missing an application like CEP or sth? What do I do?

Are you on a Mac? If I remember correctly, walls and rugs are something not always Mac-compatible. You have to check/edit something in SimPE for them to work on Macs as well. Even if you don't play on a Mac, it might be worth a shot to use Criquette's edit (under 6.3 Lot mode road overlays). Though recolors using CuriousB's mesh won't work on his cloned mesh :-( If you know how to make recolors using SimPE you can easily make some yourself and just swap textures with the textures you want.