Thanks mate..The link you provide helps me to understand about the RS232 and I'm connected to the plc. It was both Com port setting and USB to RS232 converter.
The next thing is, I'm not able to retrieve programs in the plc using "Open matching source file" from "Controller" menu. What I did was, I do "Program transfer to plc" using demo program. It says program transfer complete. Using new Untittled page, I tried to retrieve back the program and I cant. Changing the filename to the same one as I have uploaded earlier and I still cant. Both occassion it prompt filename does not exist. Hope you can help on that. Thanks.