It's an issue with Python 2.7's shutil package (which I use to recursively remove those directories, since it's easy) on Windows. It's transient and rare, but for some reason, while trying to remove the directory, shutil throws a WindowsError every once in awhile. I suspect that this is due to some kind of file/dir handle garbage collection issue, and I'm not sure if writing my own recursive directory removal routine (in a POSIX way) would actually fix the problem, so I haven't bothered trying since the error is rare and only requires running the installer again. [Man, that does sound very lazy and unlike me, though.]
Well, the lazy fix would just be to catch the exception once and try to remove again.
If you want to see Isis, the Great Goddess that moves the weather, sees all, and indeed creates the game world, search for the title Duat and view the character holding it. Internally, this title is e_hip. Another way to check out Isis is to use the console command hello 606060.
Hahaha I just checked on her, and I see that she is a carouser and enjoys sunsets. She has also established business contacts of some kind. I chuckle to imagine the Mother of the Universe going through the trade route event chain with some terrified count. I don’t see her shiny new face, though.