Oh, well, I guess I should've mentioned the version... Well, at the time I posted previously, I was using 1.7.10, I think, due to 1.8+ breaking random paintings for maps made in 1.7 or older, such as the 1.4.7 LAST DAYS map, H.E.L.L. I don't know why, though...
Anyway, when I checked the original 1.4.7 TEiEN texture pack, I noticed that the redstone dust line pngs were called redstoneDust_line.png. I can only assume that Mojang/Microsoft changed the name to avoid an error or something. I'm no programmer, but from what I learned in Web Design class, you shouldn't name files that other files use with capital letters or spaces, hence the lowercase letters, and the underscores. Though, that's besides the point. The reason I am mentioning the 1.4.7 is that I can only speculate that they change it so that then can add new files later, and/or make the creation of future resource packs easier.
But I'm just theorizing.
Anyway, thank you for your time, and good luck with bringing this great pack back to life!
PS If you need any help with figuring out the problem, just ask. I'm always happy to lend a hand whenever I can. Although, I won't be able to help with adjusting the textures directly, since I only have MSPaint, and that won't work when it comes to transparent parts.