I don't see any other discussions about it in the archives.
I too get these from time to time on my W2K box. Mostly the permission denied entries.
If "1663/17269/1677179: Permission denied" refers to a file under the data directory (I have found a folder 17269 that
containssimiliar names to 1677179) then it would seem postgres is trying to write data to a file that does not exist.