Livid_Honoka

Mojang has an official message regarding skins no longer working in minecraft pre-1.3, and that anything pre 1.7.9 can take some time to actually update.
 
You can read more about this here https://help.mojang.com/customer/portal/articles/979200-minecraft-skins
 
Please note that there is a method to make a skin work locally only (multiplayer servers will not see the skin change, and may affect all players to show in the skin) in this old of version, but give me a moment to compile a list of steps and ill edit this post.
 
Edit: Updated the above line for some clarification
 
Edit 2: Here's that list of instructions,
Rename skin file to char.png (if it isn't in a .png format, open it into an image editor and save-as to a png) Visit the following directory: .technicmodpackstekkitbin Open the minecraft.jar into an archive application (WinRAR, 7Zip, IZArc) Navigate to mob folder there Drop in the renamed char.png file for the skin, overwriting. The change should now be affected in-game (please note: 1.8 skin files may not appear correctly due to the additional information in them, if this is the case, please see this image: '> and read about the skin template changes and such on the wiki page for minecraft: http://minecraft.gamepedia.com/Skin and edit the image to be on the older style, this should just mean resizing the height down to the older size as the skin files width hasnt changed)