ifconfig not ipconfig. it matters which ip you use you cant just say oh, its out of range I'll try the next one, its out of range because thats your router's ip, theres another 192.168 ip when you use ifconfig, use it
if you're using literally 192.168.x.x then on the server open terminal or command line if its windows and type ifconfig it will show a 192.168 address, this is the internal ip, if you're using 2 other numbers, you set it up wrong if you used either 192.168.1.1 or 192.168.0.1
Then you probably did the port forwarding wrong. You used the local ip of the computer hosting the server right?
EDIT: It may also be blocked by a firewall
Just get hamachi here.
Both of you have to get it, create a server on the machine youre hosting it on and have your friend connect and use your external ip. You can use the local ip (192.168.x.x one)
Are you sure java is installed (correctly)? 1G 2G and 3G need to be multiplied by 1024 and change the G to M like -Xms2048M. If you are not using 64-bit java I'm pretty sure the max memory you can allocate is 2Gb. And also that's your startup script not antivirus :)
Backup your saves and texturepacks (~/Library/Application Support/techniclauncher/tekkit/saves (same for texturepacks)) then delete the techniclauncher folder (in ~/Library/Application Support) and start the launcher again, wait for everything to download and restore your saves and texturepacks.
Disable and reduce stuff in video settings. close everything except minecraft. allocate as much memory as possible leaving 1gb for the system. other than that I can't do anything
then the port forwarding is definitely the issue. Follow the instructions for a router of the same brand and a similar name on portforward.com. If you don't think you can figure it out you can always use hamachi.