No transport provider.

I have a customer running SBS 4.53. Using Outlook 2000 and Exchange 5.5. The problem is when they try to send email it comes back immediately with a system admin email stating that no transport provider is available. They can receive email and get on the internet fine. I have verified DNS, IP’s, DNS suffix but cannot get it to work. The event veiwer shows an error with Internet Mail Transport. In Services it is set for auto but when you try to start it there is a Error 2140 w/ NT that is generated. Is this a problem w/ Exchange 5.5? How do I start the Mail Transport? Please help!! Thanks Gale Email:galejoy@hotmail.com