Well i have run into the same problem i run x64 version of xp myself i did have a hard time finding addons that actually work with the 64bit verison, but it seems as if i have found a few, i have noticed that anything that is 7z, or cab extension wont work for some reason the 64bit version for me only works with addons that are .RAR or SVCPACK, You can try and ask the person who made the addon to see if they can make one in .rar or svcpack and everything should be fine. Hope this helps somewhat. ScOOt3r