As of BR! version 4.16 This error no longer exists. It was replaced by a combination of Error Number 4320 used in conjunction with the system variables SYSERR and SYSERR$.
Windows file is not shareable.
Using 4.03?
OS drive lost map, while BR drive map is maintained.
Drive statement contains a "."
Remedy:
Try 4.03jy or 3.91h+
re-map your drive in your OS
Change the "." to something like "\\Server\Resource" or "C:\" (without the quotes)