Microsoft Mobile Information Server

When attempting to use Server ActiveSync (MSAS) I recieve an “Error” and when I click on the “Error” Internet Explorer is executed with the following message: “Synchronization failed due to an error on your device.
Error code: HTTP_405”

What isan HTTP_405 & where can I discover what is causing the error on my device?

I am running PocketPC 2002 on a Compaq iPAQ 3650 with a Sierra Wireless AirCard 555(CDMA 1xRTT Network card) giving me access to the Internet through my cell phone provider.

We have Windows 2000 servers for the Exchange server, MMIS server, Active Directory servers and the Domain Controllers.