MS CRM Email Error Microsoft.Crm.Tools.EmailProviders.dll

We are running MS CRM 4.0 and receiving at times a log full of errors. The error reads:

Event Type:      Error
Event Source:      MSCRMEmail
Event Category:      None
Event ID:      0
Date:            8/22/2008
Time:            1:04:28 AM
User:            N/A
Computer:      SERVERNAME
Description:
#14494 - A provider work item using assembly: Microsoft.Crm.Tools.EmailProviders.dll and class: Microsoft.Crm.Tools.Email.Providers.ExchangePollingMailboxProvider has been aborted because it has been running for longer than the allowed execution time. This behavior may occur when there is a problem with the network or because the e-mail server is busy. Verify that you can log on to the e-mail server by using an e-mail application that uses the account specified for the E-mail Router.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

We would appreciate any assistance with this.
Configuration is to an MS Excahgne 2003 server.
System normally works fine, but sometimes tripps into this mode.
Only one workflow rule that appears to work fine sending email.Start Free Trial