I'm not entirely sure what you mean by my home directory/REW subdirectory.
The error log for REW is located in your home directory. Usually it will be in c:\Documents and Settings\yourusername\
The error files are stored there and are called roomeq_wizard0.txt, roomeq_wizard1.txt, etc.....
You can open them with Notepad. There's a rotating list, so choose the one with the newest date.
Attach the file to a post, so we can see the errors (if there are any).
So, I'm really not sure what is going on.
Yeah, for sure it's weird.
Just re-install REW and see what happens. You don't need to recalibrate your soundcard. The file is still located in the REW directory, with the filename that you chose, such as my_soundcard.cal