Here’s some info about ActiveSync 4.0 from MS themselves. There is a fix, you’ll need to get it yourself though. Hummpphhh…
Microsoft wants to alert you to an issue regarding ActiveSync 4.0 and the immediate steps the company is taking to resolve it and meet customer needs.
Specifically, some users of ActiveSync® 4.0 have reported challenges when using the USB connection of their personal computer to connect to a device with Windows Mobile 5.0. In many cases, these challenges are likely caused by interoperability with desktop firewall applications or applications that manage network traffic. These applications appear to conflict with the TCP traffic between a device and the PC.
An update for ActiveSync is scheduled to be available in late November, but customers may also resolve the issue manually immediately by visiting www.microsoft.com/windowsmobile.
This issue only affects people with new devices just coming to market and running Windows Mobile 5.0 software, and only when synchronizing directly to a PC when using a USB connection (wireless synchronization via Bluetooth, infra-red or directly to a server or other services are not affected). In Europe, these devices include the iMate JasJar, iMate KJam, iMate SP5, T-Mobile MDA IV, T-Mobile MDA Vario, O2 XDA Exec (Universal), Orange SPVM5000, Orange Wizard, Orange C600, the Dell Axim X51v, HP iPAQ rx1955 Pocket PC, HP iPAQ hx2495 Pocket PC, and the HP hx2795 Pocket PC.