If you can\'t ping then you have troubles. Don\'t worry (too much) about the Sharp file tranfer not working. This is (initially) caused by you not being able to ping, but I could never get it to work anyway when using usb/tcp-ip (even though I could ping, use samba, ssh, etc.).
Firewall?
Have you set the IP address on your desktop in Network settings?
Run \'ifconfig\' on your Z, see what it says, run \'ipconfig\' on your desktop.
There are lots of posts about this. Once you\'ve got it to ping in both directions then you\'re ready to try to use samba.
Si