The error codes returned by DosError are equivalent to error
     codes produced by DOS.  A value of 0 indicates no error has
     occurred.  This is the default value.  Some possible error
     codes are:

                       2 = File not found
                       3 = Path not found
                       5 = Access denied
                       6 = Invalid handle
                       8 = Not enough memory
                      10 = Invalid environment
                      11 = Invalid format
                      18 = No more files