GetLastWriteTime returning 12/31/1600 7:00:00 PM

From the documentation:

If the directory described in the path parameter does not exist, this method returns 12:00 midnight, January 1, 1601 A.D. (C.E.) Coordinated Universal Time (UTC), adjusted to local time.

So presumably your time zone is UTC-5 (in January), and the directory doesn't exist...