Can't sync Pocket PC with Active Sync

Hello,

I've been trying to get microsoft mobile devices to sync with our exchange server.  When I try to sync I get an error on the device saying that the user doesn't have permission to access the server.  I think this is related to the error I get when I try to login to the OMA site (http://servername/oma)  I get a login prompt twice the I get this error

A System error has occurred while processing your request. Please try again. If the problem persists, contact your administrator.

In the event log this error is reported

No Basic credentials were found in the HTTP request. To fix this problem, verify that Basic authentication is turned on and all other authentication methods are turned off on the Outlook(R) Mobile Access virtual directory.

and this

An unknown error occurred while processing the current request:
Message: Object reference not set to an instance of an object.
Source: Microsoft.Exchange.OMA.UserInterface
Stack trace:
   at Microsoft.Exchange.OMA.UserInterface.Global.Application_PreRequestHandlerExecute(Object sender, EventArgs e)
   at System.Web.SyncEventExecutionStep.System.Web.HttpApplication+IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)


I've tried go through several solutions I found on this site and others.  SSL is not required and I tried creating a new virtual directory and editing the exchangevdir in the registry, still getting the same error.

Please help, this has become a big issue with our sales dept and I'm hearing about it on a daily basis.

Thank You,

Keith