Can't change folder icons
So I used to have two MacBook Pros. One of them, my primary computer, I had changed several folder icons for the groups of applications I most frequently used. I had a whole collection of icons to choose from, many of which were in the system as folders themselves. This computer died recently, and I imported all the stuff off of it onto my other one, including some of the folders of applications, and the icons themselves. I had to make new folders for a few things, and these I am unable to change the icon for. I've done everything suggested elsewhere; I've changed permissions on both the folder and the icon, I've tried dragging the icon onto the folder icon in the Get Info window, I've tried copy+paste for one icon to the other, and it's not working at all. I can still change the icons of single files or programs, but not folders. Any advice?
MacBook Pro, Mac OS X (10.6.8), 17" refurbished