YAHOO! It took me ~3 hours of frustration and tinkering and scouring this thread, but I FINALLY got this to work. I thought I would share what I (think) I did to make it work.
System Specs:
OS: Windows 7 Home Premium 64 bit
CPU: Intel Core 2 Duo
Vid card: ATI Radeon 5770
Using the latest Glide64_Final caused issues, as others had pointed out. All games would crash, even without high res textures trying to be applied. I replaced the GlideHQ.dll file with the Napalm WX R1.1 release, as someone else recommended. Now games would load, but the textures would not. I kept messing around with the texture settings, until finally I saw that it was displaying a split-second text of loading textures, but looked like only the MEMORYCACHE was being read for some reason.
I'm not sure if it made a difference, but I added both the HIRESTEXTURES.dat and the MEMORYCACHE.dat into the Program Files/P64/Plugin/cache folder AND the User/AppData/Local/VirtualStore/Program Files/P64/Plugin/Cache. I discovered that P64 was using this folder when I tried to remove a different texture set I had loaded and it wasn't going anywhere, it refused to load anything but the other texture set I had loaded.
Apologies if this was covered anywhere after page 7, which is about where I was when I finally got it working. I was so close to giving up..glad I didn't this pack is SO worth it, thank you!
I've tried linking some images of my settings but for some reason it won't let me post a link to imgur...