...when I actually DO have enough disk space, and lots of it. I've tried to install it in 2 of my XP11 installations, and get the same error on whichever install or disk i use, and yes, i am using the installer via administrator privileges.
This could be due to your Windows Temp folder programs install into that folder then unpack and install to the correct location, default location is C: windows and if your C drive is running out of free space then you can get this error.