Windows Mobile 5 devices (Universal, Wizard, ...) require ActiveSync 4.x, the latest version of which can be found here
There seem to be problems using ActiveSync with firewalls other than Windows Firewall, and with some VPN clients. A troubleshooting guide by Chris De Herrera can be found on the pocketpcfaq.com website
If you cannot complete an ActiveSync connection then try these steps:
Plug into a USB port and watch the Activesync status on your PPC. If fades out to no connection then try replugging into a different USB port and attempt by cycling between USB ports at least 4 times to see if you get a successful connection.
Restart your PC and softw-rest your PPC and then try again
If still nothing then on your PC open up a Command Prompt session with Administrative Rights (Start\Programs\Accessories\Right Click on Command Prompt and Run As An Administrator)and then enter: