James,
VFP doesn't support named arguments like VB/VBA, you have to send the arguments to the methods in the proper order. Check the vbawrd8.hlp file for more info.
>ChangeFileOpenDirectory "C:\"
> ActiveDocument.SaveAs FileName:="test1.rtf", FileFormat:=wdFormatRTF, _
> LockComments:=False, Password:="", AddToRecentFiles:=True, WritePassword _
> :="", ReadOnlyRecommended:=False, EmbedTrueTypeFonts:=False, _
> SaveNativePictureFormat:=False, SaveFormsData:=False, SaveAsAOCELetter:= _
> False