Ok,...make your defragmentation.....since that is anyways necessary every so often...
But I'm also wondering whether this error message appears when trying to install LW, or after installing it and trying to start it up...?
If it is the first, you might want to try the offline installer of LW rather then using the online one...
If it is the latter one, I'd try to reinstall LW, but this time running the computer in save mode....
Just a thought though....
Cheers
FOTH