You can also see the file path for my folder... you are correct in you installation. It should be in the 'all users' directory. That's because any user that logs on to the computer will require equal access to the material library, regardless of who it is. Things like your acad.lsp, acad.pgp, profile, etc... are all user-specific things that get customized to suit each user. If you try to think of it as if the computer was being used for drafting "shift work" and you had multiple people using one machine, who each wanted to customize their system... it helps remember which files are in "all users" and which are in "specific user name" folders. For me anyways... YMMV
If you -do- select to install the materials library, and you still lack all these files, that's stupid weird that it would still be off for you. As a last resort, I can .zip up the tool palette files, and texture files, and tell you where to put each of the files, to sort of brute force it... that's more like giving Autocad the finger, instead of actually solving the initial issue, but hey, whatever gets you working again, eh? Let me know.