Don't be insulted, but it helps to double-check that you followed the update instructions completely. Did you do steps #7 (delete temp files) and #8 including the *228?
http://www.palm.com/us/support/downl...n_install.html
Troubleshooting help here:
http://www.palm.com/us/support/downl...rizon_faq.html
What version of ActiveSync? Have you tried the new beta?
http://www.microsoft.com/windowsmobi...ivesync42.mspx
Also, in the ActiveSync Connection Settings on the PC, try changing it from "automatic" to "Internet".