For Primary Setup Tool, you will need to make sure you select your PG/PC Interface first (the interface you use to look at the network).
When you say the IP is different, is it in the same subnet? What IP address and subnet mask are your PLC and PC?
Also, I didn't see a response to a very important question boneless asked at the beginning. Can you ping the PLC?
If yes, try to telnet to port 102 (telnet IP.IP.IP.IP 102) of the PLC. If it works, the command prompt should go to a blank screen and youll need to close it. If it doesn't work, it will time out. This can be used to check for blocked ports and other firewall issues.