I confirm you what i said.i ran vfp9 normally (not as administrator the code i gave
-creates the folder c:\programData\mydir without any windows dialog.
-creates the log.txt file and open it and its not marked as readonly.
I found any restriction !
Maybe another tester can confirm please this.

to confirm that i run vfp as non administrator i use this snippet (from WestWind) :return .f.

=messagebox(isadmin())

FUNCTION IsAdmin()
LOCAL loAPI, lcVal
DECLARE INTEGER IsUserAnAdmin IN Shell32
TRY
lnResult = IsUserAnAdmin()
CATCH
 *** OLD OLD Version of Windows assume .T.
lnResult = 1
ENDTRY
IF lnResult = 0
   RETURN .F.
ENDIF
RETURN .T. 
ENDFUNC